Introduction
Class 9 Maths Formulas PDF
Class 9 Maths Formulas PDF follows NCERT alignment and includes all essential formulas with clear answers and solutions. Moreover, it helps students revise key concepts quickly. Therefore, this PDF is highly useful for exam preparation, school assessments, and competitive practice.
Practice and Exam Readiness
Regular use of Class 9 Maths Formulas PDF improves calculation accuracy and problem-solving skills. Additionally, students gain confidence for CBSE and ICSE exams.
Number System Class 9 Formula PDF
Number System Class 9 Formula PDF follows NCERT alignment and includes all key formulas with clear answers and solutions. Moreover, it helps students revise concepts efficiently. Therefore, Class 9 Maths Number System Formulas PDF is highly useful for exam preparation and unit tests.
Practice and Revision
Regular practice with these formulas improves calculation speed and accuracy. Additionally, students gain confidence for CBSE and school exams.
Chapter 1: Number Systems
1. Classification of Numbers
-
Rational Numbers: Any number that can be expressed in the form p⁄q.
Q = { p⁄q : p, q ∈ Z, q ≠ 0 }
Symbols: p and q are integers.
Usage: Used to represent fractions, terminating decimals (like 0.25), and recurring decimals (like 0.333…). -
Irrational Numbers: Numbers that cannot be written in p⁄q form.
s ≠ p⁄q
Usage: These have non-terminating and non-recurring decimal expansions (e.g., π, √2).
2. Representation on Number Line
To represent an irrational number like √n on a number line, we use the Pythagoras Theorem.
-
Pythagoras Basis:
h2 = b2 + p2
Symbols: h is the hypotenuse (the value we want to plot), b is the base, and p is the perpendicular height.
Usage: If you want to plot √2, take base = 1 unit and height = 1 unit.
Representing √2 on the Number Line using Pythagoras Theorem
3. Operations on Real Numbers
When we combine rational and irrational numbers, the following identities are essential:
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Square Root Products:
√(ab) = √a • √b
Usage: Used to simplify radicals, e.g., √6 = √2 • √3.
-
Square Root Quotients:
√(a⁄b) = √a⁄√b
Usage: Used to split roots across fractions.
-
Algebraic Identities for Roots:
(√a + √b)(√a – √b) = a – b (a + √b)(a – √b) = a2 – b
Usage: These are the primary tools used for Rationalizing the Denominator.
4. Rationalization
If the denominator of an expression contains a square root, we multiply the numerator and denominator by the conjugate.
-
Rationalizing Factor:
Usage: Used to simplify expressions to a standard form where no radicals remain in the denominator.
5. Laws of Exponents for Real Numbers
Let a be a real number and p, q be rational numbers:
- 1. Product Law: ap • aq = ap + q
- 2. Quotient Law: ap / aq = ap – q
- 3. Power of a Power: (ap)q = apq
- 4. Product Power Law: (ab)p = apbp
- 5. Negative Exponent: a-p = 1 / ap
- 6. Radical to Exponent: n√a = a1/n
Polynomials Class 9 Formulas PDF
Polynomials Class 9 Formulas PDF follows NCERT alignment and covers all key formulas with detailed answers and solutions. Moreover, it helps students understand algebraic expressions quickly. Therefore, Class 9 Maths Polynomials All Formulas PDF is highly useful for exams and unit tests.
Practice and Exam Readiness
Regular practice with these formulas improves accuracy and confidence. Additionally, students can revise efficiently for CBSE and school examinations.
Polynomials
1.1 Definition of Polynomial in One Variable
A polynomial in one variable x is an algebraic expression of the form:
where an, an-1, …, a0 are real numbers and n is a non-negative integer.
Here, an is the leading coefficient and a0 is the constant term. Polynomials are used to represent algebraic relationships in equations and graphs.
1.2 Coefficients, Terms and Degree
- In the polynomial:
p(x) = 3x2 – 5x + 7the coefficients are 3, -5, and 7.
- Each part such as 3x2, -5x, and 7 is called a term.
- The highest power of the variable is called the degree of the polynomial.
Degree helps in classifying polynomials and predicting the shape of their graphs.
1.3 Types of Polynomials
- Zero polynomial: p(x) = 0 (Degree is not defined).
- Linear polynomial: p(x) = ax + b (Degree is 1).
- Quadratic polynomial: p(x) = ax2 + bx + c (Degree is 2).
- Cubic polynomial: p(x) = ax3 + bx2 + cx + d (Degree is 3).
1.4 Monomials, Binomials and Trinomials
- Monomial has one term, example: 5x
- Binomial has two terms, example: x + 3
- Trinomial has three terms, example: x2 + 2x + 1
1.5 Addition and Subtraction of Polynomials
- Addition:
(2x2 + 3x + 1) + (x2 – x + 4) = 3x2 + 2x + 5
- Subtraction:
(2x2 + 3x + 1) – (x2 – x + 4) = x2 + 4x – 3
Like terms are added or subtracted to simplify expressions.
1.6 Multiplication of Polynomials
Each term of one polynomial is multiplied with every term of the other polynomial.
1.7 Division Algorithm for Polynomials
If p(x) and g(x) are polynomials with g(x) ≠ 0, then:
where q(x) is the quotient and r(x) is the remainder.
1.8 Zero of a Polynomial
A real number a is a zero of p(x) if:
Zeros represent the x-intercepts of the graph of the polynomial.
1.9 Remainder Theorem
If a polynomial p(x) is divided by (x – a), then the remainder is p(a).
1.10 Factorization Using Identities
- (x + y)2 = x2 + 2xy + y2
- (x – y)2 = x2 – 2xy + y2
- x2 – y2 = (x + y)(x – y)
- (x + a)(x + b) = x2 + (a + b)x + ab
1.11 Factorization of Trinomials
The trinomial is factorized by finding two numbers whose sum and product match the middle and constant terms.
1.12 Quick Revision Summary
- General form: p(x) = anxn + … + a0
- Division: p(x) = g(x)q(x) + r(x)
- Zero: p(a) = 0
- Square Identity: (x + y)2 = x2 + 2xy + y2
- Difference of Squares: x2 – y2 = (x + y)(x – y)
Coordinate Geometry Class 9 Formulas PDF
Coordinate Geometry Class 9 Formulas PDF follows NCERT alignment and includes all essential formulas with clear answers and solutions. Moreover, it supports quick concept revision. Therefore, Class 9 Maths Coordinate Geometry Formula Sheet PDF is highly useful for exam preparation and school assessments.
Practice and Revision
Using this formula sheet improves calculation accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter 7: Coordinate Geometry
This chapter introduces the language to describe the position and location of points on a plane using numbers. You will learn how to find distances, midpoints, and areas using these number pairs called coordinates.
1. The Cartesian Plane
The foundation of coordinate geometry is a plane formed by two perpendicular number lines.
- Cartesian Plane / Coordinate Plane: Plane = x-axis ⊥ y-axis
- x-axis: The horizontal number line.
- y-axis: The vertical number line.
- Origin (O): The point of intersection (0, 0).
- Quadrants: The axes divide the plane into four regions (I, II, III, IV).
2. Coordinates of a Point
Every point on the plane can be uniquely identified by an ordered pair of numbers.
- x-coordinate (Abscissa): The perpendicular distance from the y-axis.
- y-coordinate (Ordinate): The perpendicular distance from the x-axis.
- Usage: To plot a point P(3, -2), move 3 units right and 2 units down.
3. Distance Formula
Used to find the length of the line segment joining two points.
- A(x1, y1) & B(x2, y2): Coordinates of the endpoints.
- Usage: Directly apply the formula. Squaring the differences removes any negative sign issues.
4. Section Formula
Used to find the coordinates of a point that divides a line segment in a given ratio.
- m : n: Ratio in which P divides AB internally.
5. Area of a Triangle
The absolute value bars | | ensure the area is always positive. If the area is zero, the points are collinear.
Quick Revision Summary
- Distance: d = √[(Δx)2 + (Δy)2]
- Section Point: Weightage sum formula: x = (mx2+nx1)/(m+n)
- Midpoint: Average of coordinates: xavg, yavg
- Collinearity: Three points are collinear if Area = 0.
Linear Equations in Two Variables Class 9 Formulas PDF
Linear Equations in Two Variables Class 9 Formulas PDF follows NCERT alignment and includes all formulas with detailed answers and solutions. Moreover, it helps students understand equation-solving techniques clearly. Therefore, Class 9 Linear Equations in Two Variables Formula Sheet PDF is highly useful for exam preparation and practice.
Practice and Exam Readiness
Regular practice with this formula sheet improves accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and school exams.
Chapter: Linear Equations in Two Variables
Definitions
-
ax + by + c = 0
Here, x and y are variables, and a, b, c are real numbers such that a ≠ 0 and b ≠ 0.
This is called a linear equation in two variables. It represents a straight line when drawn on a graph.
Standard Forms of Linear Equations
-
ax + by + c = 0
a and b are coefficients of x and y, and c is a constant.
This is the most general form used to represent a linear equation in two variables.
-
y = mx + c
Here, m is the slope of the line and c is the y-intercept.
This form is useful for quickly drawing the graph of a line.
Solutions of a Linear Equation
-
(ax + by + c = 0) ⇒ (x, y)
An ordered pair (x, y) that satisfies the equation is called a solution.
Infinitely many solutions exist because a straight line has infinitely many points.
Graph of a Linear Equation
ax + by + c = 0
To draw the graph:
- Find two solutions of the equation.
- Plot the points on the Cartesian plane.
- Join the points to get a straight line.
This diagram shows the graph of a linear equation as a straight line.
Intercept Form
Here, a is the x-intercept and b is the y-intercept.
This form is used when intercepts on axes are known directly.
Real Life Applications
Here, x and y represent quantities like ages, numbers, or money, and k is a constant.
This type of equation is used to solve problems related to age, numbers, and daily life situations.
Quick Revision Summary (Formulas Only)
- General Form: ax + by + c = 0
- Slope-Intercept Form: y = mx + c
- Intercept Form: x/a + y/b = 1
- Sum Form: x + y = k
Euclid’s Geometry Class 9 Formulas PDF
Euclid’s Geometry Class 9 Formulas PDF follows NCERT alignment and provides all key formulas with clear answers and solutions. Moreover, it helps students revise theorems efficiently. Therefore, Class 9 Maths Chapter 5 Euclid’s Geometry Formulas PDF is highly useful for exams and school assessments.
Practice and Exam Preparation
Regular practice with these formulas improves understanding and calculation speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter : Introduction to Euclid’s Geometry
This chapter introduces you to the foundational thinking of geometry as developed by the ancient Greek mathematician Euclid. You will learn about the building blocks of logical reasoning in mathematics: definitions, axioms, and postulates.
1. Fundamental Building Blocks
Geometry starts with simple, accepted truths from which complex results (theorems) are logically derived.
- A Definition
- A definition is a precise statement that explains the meaning of a new term using already known terms.
- Example: “A point is that which has no part.” or “A line is breadthless length.”
- Usage: Definitions create a common language for geometry.
- An Axiom or a Postulate
Axiom/Postulate = A statement accepted as true without proof
- Axioms are common notions accepted in all sciences.
- Postulates are specific assumptions for geometry.
- Usage: These are the starting points for all proofs. You must remember and apply them.
- A Theorem
Theorem = A statement proved using definitions, axioms, postulates, and previously proved theorems
- Usage: The goal is to logically deduce theorems from the basic assumptions.
2. Euclid’s Five Postulates
These are the five foundational assumptions on which Euclid built his entire geometry.
- Postulate 1: A straight line can be drawn from any point to any other point.
- Given any two distinct points, there is a unique line that passes through them.
- Postulate 2: A terminated line (line segment) can be produced indefinitely in both directions.
- A line segment can be extended to form a full line.
- Postulate 3: A circle can be drawn with any centre and any radius.
- Postulate 4: All right angles are equal to one another.
- A right angle is a standard measure. Every right angle measures 90°.
- Postulate 5 (The Famous Parallel Postulate): If a straight line falling on two straight lines makes the interior angles on the same side of it taken together less than two right angles, then the two straight lines, if produced indefinitely, meet on that side on which the sum of angles is less than two right angles.
3. Key Axioms (Common Notions)
These are general logical principles used throughout mathematics.
- Axioms of Equality and Magnitude
- Things which are equal to the same thing are equal to one another. (If a = c and b = c, then a = b).
- If equals are added to equals, the wholes are equal.
- If equals are subtracted from equals, the remainders are equal.
- Things which coincide with one another are equal to one another.
- The whole is greater than the part.
4. Equivalent Versions of Euclid’s Fifth Postulate
Because the original 5th postulate was complex, mathematicians searched for simpler, logically equivalent statements. The most famous is Playfair’s Axiom.
- Playfair’s Axiom
For every line l and for every point P not lying on l, there exists a unique line m passing through P and parallel to l.
- l: A given straight line.
- P: A point not on l.
- m: The unique line through P parallel to l.
- Usage: This is the modern form of the parallel postulate used in most school geometries. It’s much easier to understand and apply.
5. Some Important Theorems/Results
- Two distinct lines cannot have more than one point in common.
- If two lines share two points, they are the same line (from Postulate 1).
- Two distinct intersecting lines cannot be parallel to the same line.
Quick Revision Summary
- Definitions explain the meaning of new terms.
- Axioms/Postulates are assumptions accepted without proof.
- Theorems are statements that are proved.
- Postulate 1: A unique line through any two points.
- Postulate 2: A line segment can be extended indefinitely.
- Postulate 3: A unique circle for any centre and radius.
- Postulate 4: All right angles are equal.
- Postulate 5: Parallel Postulate (lines meet on side where interior angles < 180°).
- Playfair’s Axiom: Through a point not on a line, there is exactly one line parallel to the given line.
- Common Axioms: Things equal to the same thing are equal; the whole is greater than the part.
Lines and Angles Class 9 Formulas PDF
Lines and Angles Class 9 Formulas PDF follows NCERT alignment and provides all important formulas with clear answers and solutions. Moreover, it helps students revise concepts quickly. Therefore, Class 9 Maths Lines and Angles Formula Sheet is highly useful for exams and school assessments.
Practice and Exam Readiness
Using this formula sheet improves accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE examinations.
Chapter : Lines and Angles
This chapter explores the fundamental relationships between lines and the angles they form. Understanding these relationships is crucial for all later work in geometry.
1. Basic Angle Pairs
When lines meet or cross, they create special pairs of angles with specific relationships.
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Complementary Angles
∠A + ∠B = 90°
- ∠A, ∠B: Two angles.
- Meaning: Their measures add up to a right angle (90°).
- Usage: If one angle is known, the other is 90° − (known angle).
-
Supplementary Angles
∠C + ∠D = 180°
- ∠C, ∠D: Two angles.
- Meaning: Their measures add up to a straight angle (180°).
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Linear Pair of Angles
∠1 + ∠2 = 180°
- Meaning: They are adjacent and supplementary.
- Usage: A very common result used in proofs.
-
Vertically Opposite Angles
∠a = ∠c and ∠b = ∠d
- Meaning: Angles opposite each other at the intersection of two lines are equal.
2. Angles Made by a Transversal
When a line (transversal) crosses two other lines, it creates eight angles with special relationships.
Angle Properties When a Transversal Intersects Two Parallel Lines
- Corresponding Angles: ∠1 = ∠5, ∠2 = ∠6, ∠3 = ∠7, ∠4 = ∠8
- Alternate Interior Angles: ∠3 = ∠6, ∠4 = ∠5
- Alternate Exterior Angles: ∠1 = ∠8, ∠2 = ∠7
- Co-interior Angles: ∠3 + ∠5 = 180°, ∠4 + ∠6 = 180°
- Vertically Opposite Angles: ∠1 = ∠4, ∠2 = ∠3, ∠5 = ∠8, ∠6 = ∠7
3. Parallel Line Properties
- Converse of Corresponding Angles: If ∠1 = ∠5, then l ∥ m.
- Converse of Alternate Angles: If ∠3 = ∠5, then l ∥ m.
- Converse of Co-interior Angles: If ∠3 + ∠6 = 180°, then l ∥ m.
4. Triangle Angle Properties
-
Angle Sum Property of a Triangle
∠A + ∠B + ∠C = 180°
The sum of all interior angles of a triangle is always 180°.
-
Exterior Angle Property of a Triangle
∠CBD = ∠CAB + ∠ACB
An exterior angle of a triangle is equal to the sum of its two interior opposite angles.
[Image showing the exterior angle of a triangle as the sum of two interior opposite angles]
5. Lines Parallel to the Same Line
-
Transitivity of Parallelism
If l ∥ m and m ∥ n, then l ∥ n
Quick Revision Summary
- Complementary: Sum = 90° | Supplementary: Sum = 180°
- Linear Pair: Adjacent angles on a straight line add to 180°.
- Vertically Opposite: Intersecting lines create equal opposite angles.
- Parallel Lines: Corresponding angles equal, Alternate angles equal, Co-interior angles = 180°.
- Triangle: Interior sum = 180° | Exterior ∠ = Sum of two interior opposite ∠s.
- Parallel Transitivity: Lines parallel to the same line are parallel to each other.
Triangles Formulas Class 9 PDF
Triangles Formulas Class 9 PDF follows NCERT alignment and includes all important formulas with clear answers and solutions. Moreover, it helps students revise properties and theorems quickly. Therefore, Class 9 Maths Triangles All Formulas PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular practice with this formula sheet improves calculation accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter : Triangles
This chapter explores when two triangles are identical in shape and size (congruent), and the fundamental relationships between the sides and angles within a single triangle.
1. Congruence of Triangles
Two triangles are congruent if all corresponding sides and angles are equal. The following criteria help us prove congruence without checking all six elements.
-
Side-Side-Side (SSS) Congruence Rule
- Condition: If three sides of one triangle are equal to three sides of another triangle.
- Usage: When all side lengths are known or can be proved equal.
If AB = PQ, BC = QR, CA = RP then ΔABC ≅ ΔPQR -
Side-Angle-Side (SAS) Congruence Rule
- Condition: If two sides and the included angle of one triangle are equal to two sides and the included angle of another triangle.
- Usage: When two sides and the angle between them are known to be equal.
If AB = PQ, ∠B = ∠Q, BC = QR then ΔABC ≅ ΔPQR - Angle-Side-Angle (ASA) Congruence Rule
- Condition: If two angles and the included side of one triangle are equal to two angles and the included side of another triangle.
If ∠B = ∠Q, BC = QR, ∠C = ∠R then ΔABC ≅ ΔPQR - Angle-Angle-Side (AAS) Congruence Rule
- Condition: If two angles and a non-included side of one triangle are equal to the corresponding angles and side of another triangle.
If ∠A = ∠P, ∠B = ∠Q, BC = QR then ΔABC ≅ ΔPQR - Right Angle-Hypotenuse-Side (RHS) Congruence Rule
- Condition: If the hypotenuse and one side of a right triangle are equal to the hypotenuse and one side of another right triangle.
If ∠B = ∠Q = 90°, AC = PR, BC = QR then ΔABC ≅ ΔPQR
2. Properties of Triangle Inequalities
-
Triangle Inequality Theorem
AB + BC > AC, BC + CA > AB, CA + AB > BC[Image showing a triangle with labeled sides AB, BC, and CA]
Meaning: The sum of any two sides of a triangle is greater than the third side.
- Angle Opposite to Longer Side
If AB > AC then ∠C > ∠B
Meaning: In any triangle, the angle opposite the longer side is larger.
- Side Opposite to Larger Angle
If ∠C > ∠B then AB > AC
Meaning: In any triangle, the side opposite the larger angle is longer.
- Sum of Any Two Sides
AB + AC > BC
Note: The shortest distance between two points (B and C) is the straight line BC.
3. Important Results about Triangles
-
Pythagoras Theorem (For Right Triangles Only)
AC2 = AB2 + BC2
- Condition: Only applies when ∠B = 90°.
- AC: Hypotenuse (side opposite the right angle).
- AB, BC: The other two sides (legs).
- Exterior Angle Inequality
∠ACD > ∠A and ∠ACD > ∠B
Meaning: An exterior angle of a triangle is greater than either of the opposite interior angles.
Quick Revision Summary
- SSS: Three sides equal.
- SAS: Two sides and the included angle equal.
- ASA: Two angles and the included side equal.
- AAS: Two angles and a non-included side equal.
- RHS: Hypotenuse and one side of right triangles equal.
- Triangle Inequality: Sum of two sides > third side.
- Longer Side ↔ Larger Angle: Side-angle opposite relationship.
- Pythagoras: AC2 = AB2 + BC2 (for 90°).
Quadrilaterals Class 9 Formulas PDF
Quadrilaterals Class 9 Formulas PDF follows NCERT alignment and provides all key formulas with clear answers and solutions. Moreover, it helps students revise properties quickly. Therefore, Class 9 Maths Quadrilaterals Formula Sheet PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Using this formula sheet improves calculation accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter 8: Quadrilaterals
This chapter explores the properties of four-sided figures called quadrilaterals. You will learn about special types of quadrilaterals and their unique characteristics, as well as an important theorem about triangles.
1. Basic Properties of Quadrilaterals
Every quadrilateral shares these fundamental properties.
1. Angle Sum Property of a Quadrilateral
- ∠A, ∠B, ∠C, ∠D: The four interior angles of any quadrilateral.
- Meaning: The sum of all interior angles of a quadrilateral is always 360°.
- Usage: To find the fourth angle when three angles are known, or to verify if four given angles can form a quadrilateral.
2. Sum of All Exterior Angles of a Quadrilateral
- Meaning: For any polygon (including quadrilateral), the sum of exterior angles, one at each vertex, is always 360°, regardless of the number of sides.
- Usage: Useful in problems involving exterior angles.
2. Special Quadrilaterals and Their Properties
Different types of quadrilaterals have additional special properties. Remember: each type inherits all properties of the types above it in the hierarchy.
Hierarchy of Quadrilaterals
3. Properties of a Parallelogram
- Opposite sides are parallel and equal: AB ∥ DC, AB = DC and AD ∥ BC, AD = BC
- Opposite angles are equal: ∠A = ∠C and ∠B = ∠D
- Diagonals bisect each other: AO = OC and BO = OD
- Adjacent angles are supplementary: ∠A + ∠B = 180°
4. Properties of a Rectangle (A type of parallelogram)
- All properties of parallelogram apply.
- Each interior angle = 90°
- Diagonals are equal in length.
5. Properties of a Rhombus (A type of parallelogram)
- All properties of parallelogram apply.
- All sides are equal: AB = BC = CD = DA
- Diagonals are perpendicular to each other.
- Diagonals bisect the opposite angles.
6. Properties of a Square (A type of rectangle and rhombus)
- All properties of rectangle and rhombus apply.
- All sides equal, all angles 90°.
- Diagonals equal and perpendicular.
7. Properties of a Kite
- Two pairs of adjacent sides equal: AB = AD and CB = CD
- One diagonal bisects the other at 90°.
- One pair of opposite angles are equal.
3. Mid-point Theorem
This important theorem connects the midpoints of sides of a triangle.
8. Mid-point Theorem Statement
- D, E: Midpoints of sides AB and AC of △ABC.
- DE: Line segment joining the midpoints.
- Meaning: The line segment joining midpoints of two sides is parallel to the third side and half its length.
- Usage: To prove parallelism or find lengths in triangle problems.
9. Converse of Mid-point Theorem
- Usage: To prove a point is a midpoint when parallelism is known.
4. Conditions for Special Quadrilaterals
These help prove what type of quadrilateral a given figure is.
10. Condition for a Parallelogram
- If both pairs of opposite sides are parallel.
- If both pairs of opposite sides are equal.
- If diagonals bisect each other.
- If a pair of opposite sides are both parallel and equal.
11. Condition for a Rectangle
- If it is a parallelogram with one angle 90°.
- If diagonals are equal and bisect each other.
12. Condition for a Rhombus
- If it is a parallelogram with adjacent sides equal.
- If diagonals are perpendicular and bisect each other.
13. Condition for a Square
- If it is a rectangle with adjacent sides equal.
- If it is a rhombus with one angle 90°.
Quick Revision Summary
Here are all the essential formulas and properties from this chapter.
- Angle Sum Property: ∠A + ∠B + ∠C + ∠D = 360°
- Parallelogram Properties:
- Opposite sides ∥ and equal
- Opposite angles equal
- Diagonals bisect each other
- Rectangle Properties: All parallelogram properties + Each angle 90° + Diagonals equal
- Rhombus Properties: All parallelogram properties + All sides equal + Diagonals ⟂
- Square Properties: All rectangle and rhombus properties
- Kite Properties: Two pairs adjacent sides equal + One diagonal ⟂ bisector of other
- Mid-point Theorem: DE ∥ BC and DE = ½ BC
- Converse of Mid-point Theorem: If D is midpoint of AB and DE ∥ BC, then E is midpoint of AC
Areas of Parallelograms and Triangles Class 9 Formulas PDF
Areas of Parallelograms and Triangles Class 9 Formulas PDF follows NCERT alignment and includes all essential formulas with clear answers and solutions. Moreover, it helps students revise concepts quickly. Therefore, Class 9 Maths Areas of Parallelograms and Triangles Formula Sheet PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular practice with this formula sheet improves accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter : Areas of Parallelograms and Triangles
This chapter explores how to calculate areas of parallelograms and triangles, and the important relationships between their areas when they share common bases and heights.
1. Basic Area Formulas
These are the fundamental formulas for calculating areas.
-
Area of a Parallelogram
A = b × h
- A: Area of the parallelogram.
- b: Length of any base of the parallelogram.
- h: Perpendicular height (distance between the base and its opposite side).
- Usage: Multiply the base length by the perpendicular height. Make sure the height is measured perpendicular to the base, not along the slanted side.
-
Area of a Triangle
A = ½ × b × h
- A: Area of the triangle.
- b: Length of any side (base).
- h: Perpendicular height from the opposite vertex to that base.
- Usage: Multiply base by height, then take half. Any side can be the base, but use the corresponding height.
2. Figures on the Same Base and Between Same Parallels
Two figures are said to be on the same base and between the same parallels if:
- They share a common base.
- Their opposite vertices (or sides) lie on a line parallel to the base.
3. Important Theorems about Area Relationships
-
Parallelograms on the Same Base and Between Same Parallels
Area(ABCD) = Area(ABEF)
Meaning: Parallelograms on the same base and between the same parallels have equal areas.
-
Triangles on the Same Base and Between Same Parallels
Area(▵ ABC) = Area(▵ ABD)
Condition: Both triangles must share base AB and have their third vertices on a line parallel to AB.
-
Relationship Between Area of Parallelogram and Triangle
Area(ABCD) = 2 × Area(▵ ABD)
Condition: When a parallelogram and a triangle are on the same base and between the same parallels.
-
Diagonals of a Parallelogram Divide it into Equal Triangles
Area(▵ ABC) = Area(▵ ADC)
Meaning: A diagonal of a parallelogram divides it into two triangles of equal area.
4. Median of a Triangle and Area
-
Median Divides Triangle into Two Equal Areas
Area(▵ ABM) = Area(▵ ACM) = ½ Area(▵ ABC)
- M: Midpoint of side BC.
- AM: Median from vertex A.
Quick Revision Summary
- Area of Parallelogram: A = b × h
- Area of Triangle: A = ½ × b × h
- Same base, same parallels: Parallelograms (and Triangles) have equal areas.
- Para vs Triangle: Area(Para) = 2 × Area(Triangle) on same base/parallels.
- Diagonal: Divides parallelogram into 2 equal triangles.
- Median: Divides triangle into 2 equal areas.
Circles Formulas Class 9 PDF
Circles Formulas Class 9 PDF follows NCERT alignment and provides all important formulas with clear answers and solutions. Moreover, it helps students revise theorems and properties quickly. Therefore, Class 9 Maths Circles Formula Sheet PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular practice with this formula sheet improves calculation accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter 10: Circles
This chapter explores the properties of circles, chords, arcs, and cyclic quadrilaterals. You’ll learn important relationships between chords, angles, and distances from the center.
1. Key Definitions
- Radius: Distance from centre to any point on circle.
- Diameter: Longest chord passing through centre; diameter = 2 × radius.
- Chord: Line segment joining any two points on circle.
- Arc: Part of circumference between two points.
- Secant: Line intersecting circle at two points.
- Tangent: Line touching circle at exactly one point.
- Sector: Region between two radii and arc.
- Segment: Region between chord and arc.
2. Chord Properties
These theorems describe relationships involving chords and the circle’s centre.
A. Perpendicular from Centre to Chord
- O: Centre of circle.
- AB: Chord.
- M: Point where perpendicular from O meets chord.
- Meaning: The perpendicular from centre to a chord bisects the chord.
- Usage: To find chord length or distance from centre.
B. Equal Chords and Distance from Centre
Meaning: Equal chords are equidistant from centre, and chords equidistant from centre are equal.
C. Angle Subtended by a Chord at Centre
Meaning: The angle subtended by a chord at centre is double the angle subtended at any point on the remaining part of the circle.
3. Circle Through Three Points
Theorem: There is one and only one circle passing through three given non-collinear points.
4. Cyclic Quadrilaterals
A quadrilateral whose all vertices lie on a circle is called cyclic.
A. Opposite Angles
B. Exterior Angle
5. Important Circle Theorems
-
Angles in Same Segment:
∠ ACB = ∠ ADB
Angles in the same segment of a circle are equal.
-
Angle in Semicircle:
∠ ACB = 90°
The angle in a semicircle is always a right angle (where AB is the diameter).
Quick Revision Summary
- Perpendicular from centre: Bisects the chord.
- Equal chords: Equidistant from the centre.
- Angle at centre: Double the angle at the circumference.
- Circle through 3 points: Only one unique circle.
- Cyclic quad: Opposite angles add up to 180°.
- Angles in same segment: Always equal.
- Angle in semicircle: Always 90°.
Heron’s Formula Class 9 Maths PDF
Heron’s Formula Class 9 Maths PDF follows NCERT alignment and provides all key formulas with clear answers and solutions. Moreover, it helps students calculate triangle areas efficiently. Therefore, Heron’s Formula Questions Class 9 with Solutions PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular practice with these formulas improves accuracy and problem-solving skills. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter : Heron’s Formula
This chapter introduces a powerful formula to calculate the area of a triangle when all three side lengths are known. Unlike the standard formula (½ × base × height), Heron’s formula doesn’t require you to know the height of the triangle.
1. Heron’s Formula for Area of Triangle
This is the main formula of the chapter, named after the Greek mathematician Heron of Alexandria.
-
Heron’s Formula
Area = √[s(s – a)(s – b)(s – c)]
- a, b, c: Lengths of the three sides of the triangle.
- s: Semi-perimeter of the triangle.
- s = (a + b + c) / 2: Half of the triangle’s perimeter.
- Usage: Use when you know all three sides but not the height. Follow these steps:
- Calculate semi-perimeter s = (a + b + c) / 2
- Substitute s, a, b, c into the formula
- Compute the product under the square root
- Take the square root for the area
-
Semi-perimeter Formula
s = (a + b + c) / 2
Usage: Always calculate this first before applying Heron’s formula.
2. Alternative Form of Heron’s Formula
Sometimes it’s useful to see the expanded form.
-
Expanded Form
Area = ¼√[(a+b+c)(-a+b+c)(a-b+c)(a+b-c)]
- Note: This is algebraically equivalent to the main formula. The expression under the square root is the same as 16s(s-a)(s-b)(s-c).
3. Special Case: Equilateral Triangle
For an equilateral triangle (all sides equal), Heron’s formula simplifies beautifully.
-
Area of Equilateral Triangle
Area = (√3 / 4) a2
- a: Length of each side of the equilateral triangle.
- Derivation: When a = b = c, then s = 3a/2.
4. Application to Quadrilaterals
Heron’s formula can be extended to find areas of certain quadrilaterals by dividing them into triangles.
-
Area of Quadrilateral (diagonal known)
Area = Area(▵ABC) + Area(▵ADC)
-
Brahmagupta’s Formula (Cyclic Quadrilateral)
Area = √[(s-a)(s-b)(s-c)(s-d)]
5. Step-by-Step Application Guide
-
Problem-Solving Steps
- Identify the three sides a, b, c.
- Calculate semi-perimeter: s = (a+b+c)/2.
- Compute differences: (s-a), (s-b), (s-c).
- Multiply: s × (s-a) × (s-b) × (s-c).
- Take square root of the product.
6. Real-Life Applications
- Common Applications
- Land measurement: Finding area of triangular plots.
- Construction: Calculating materials for structures.
- Surveying: When heights are inaccessible.
-
Example: Triangular Field
Find area using Heron’s Formula
7. Important Notes and Tips
- Triangle Inequality Check: Verify a + b > c, b + c > a, c + a > b.
- Units: Ensure all sides are in the same units.
- Decimal vs Exact: Keep calculations exact as long as possible.
Quick Revision Summary
- Semi-perimeter: s = (a + b + c) / 2
- Heron’s Formula: Area = √[s(s – a)(s – b)(s – c)]
- Equilateral Triangle: Area = (√3 / 4) a2
- Quadrilateral: Divide into triangles and sum areas.
- Triangle Inequality: Sum of any two sides must be greater than the third.
Surface Areas and Volumes Class 9 Formulas PDF
Surface Areas and Volumes Class 9 Formulas PDF follows NCERT alignment and provides all essential formulas with clear answers and solutions. Moreover, it helps students understand 3D shapes quickly. Therefore, Class 9 Maths Surface Areas and Volumes Formula Sheet is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular practice with this formula sheet improves calculation accuracy and problem-solving speed. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter: Surface Areas and Volumes
This chapter deals with calculating the surface area (total outside covering) and volume (space occupied) of various 3D shapes like cubes, cuboids, cylinders, cones, and spheres.
1. Cuboid
A cuboid is a box-shaped object with 6 rectangular faces.
-
Surface Area of Cuboid
TSA = 2(lb + bh + hl)
- TSA: Total Surface Area (all 6 faces).
- l: Length, b: Breadth, h: Height.
- Usage: Sum areas of all faces: two each of l × b, b × h, h × l.
-
Lateral Surface Area of Cuboid
LSA = 2h(l + b)
- LSA: Lateral Surface Area (only the 4 side faces).
- Usage: Useful when calculating area to paint the walls of a room.
- Volume of Cuboid: V = l × b × h
- Diagonal of Cuboid: d = √(l2 + b2 + h2)
2. Cube
A cube is a special cuboid where l = b = h = a.
- Surface Area of Cube: TSA = 6a2
- Lateral Surface Area: LSA = 4a2
- Volume of Cube: V = a3
- Diagonal of Cube: d = a√3
3. Right Circular Cylinder
- Curved Surface Area (CSA): 2πrh
- Total Surface Area (TSA): 2πr(h + r)
- Volume: πr2h
4. Right Circular Cone
- Slant Height (l): l = √(h2 + r2)
- CSA: πrl
- Volume: 1/3 πr2h
5. Sphere & Hemisphere
- Sphere Surface Area: 4πr2
- Sphere Volume: 4/3 πr3
- Hemisphere TSA: 3πr2 (CSA 2πr2 + base πr2)
- Hemisphere Volume: 2/3 πr3
Quick Revision Summary
- Cuboid: V = lbh, TSA = 2(lb+bh+hl)
- Cylinder: V = πr2h, CSA = 2πrh
- Cone: V = 1/3πr2h, CSA = πrl
- Sphere: V = 4/3πr3, SA = 4πr2
- Units: 1 L = 1000 cm3; 1 m3 = 1000 L
Statistics Formulas Class 9 PDF
Statistics Formulas Class 9 PDF follows NCERT alignment and includes all key formulas with clear answers and solutions. Moreover, it helps students analyze data and solve problems efficiently. Therefore, Class 9 Maths Statistics Formulas PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular use of this formula sheet improves calculation accuracy and understanding. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter : Statistics
This chapter deals with collecting, organizing, presenting, and analyzing data. You’ll learn different ways to represent data visually and calculate measures that describe the “center” or “average” of a dataset.
“`1. Basic Definitions
- Data
- A collection of facts, numbers, or information.
- Example: Marks of students: 85, 90, 78, 92, 88.
- Frequency
Frequency = Number of times a value occurs
- Usage: Count how many times each data value appears in the dataset.
- Class Interval
Range of values grouped together (e.g., 10-20, 20-30)
- Lower Limit: Smallest value in class (e.g., 10).
- Upper Limit: Largest value in class (e.g., 20).
- Class Mark (xi): Mid-point = (Lower Limit + Upper Limit) / 2
2. Measures of Central Tendency (Ungrouped Data)
These are single values that represent the “center” or typical value of a dataset.
- Mean (Average)
x̄ = (∑ xi) / n = (x1 + x2 + … + xn) / n
- x̄: Mean (read as “x-bar”).
- xi: Individual data values.
- n: Total number of observations.
- Median (Middle Value)
If n is odd: Value at [(n+1)/2]th position
If n is even: Average of (n/2)th and (n/2 + 1)th positions - Mode (Most Frequent Value)
- The value that occurs with the highest frequency.
- Best for categorical data (e.g., most popular shoe size).
3. Graphical Representation of Data
- Bar Graph: Used for discrete/categorical data with gaps between bars.
- Histogram: Used for continuous data with no gaps between bars.
- Frequency Polygon
- Formed by joining the mid-points (class marks) of the histogram bars with straight lines.
4. Mean for Grouped Data
- Direct Method: x̄ = (∑ fixi) / ∑ fi
- Assumed Mean Method: x̄ = a + (∑ fidi) / ∑ fi (where di = xi – a)
- Step Deviation Method: x̄ = a + [ (∑ fiui) / ∑ fi ] × h (where ui = (xi – a) / h)
5. Mode for Grouped Data
- Mode Formula
Mode = l + [ (f1 – f0) / (2f1 – f0 – f2) ] × h
- l: lower limit of modal class.
- f1: frequency of modal class.
- f0: frequency of class preceding modal class.
- f2: frequency of class succeeding modal class.
6. Median for Grouped Data
- Median Formula
Median = l + [ (n/2 – cf) / f ] × h
- Cumulative Frequency (cf): The “running total” of frequencies.
7. Empirical Relationship
Quick Revision Summary
- Class Mark: (Upper Limit + Lower Limit) / 2
- Mean: ∑ fixi / ∑ fi
- Mode: Value with max frequency (or formula for grouped)
- Median: Middle value (positional average)
- Empirical Formula: 3Med = Mode + 2Mean
Probability Formulas Class 9 PDF
Probability Formulas Class 9 PDF follows NCERT alignment and provides all key formulas with clear answers and solutions. Moreover, it helps students understand probability concepts quickly. Therefore, Class 9 Maths Probability Formulas PDF is highly useful for exam preparation and school assessments.
Practice and Exam Readiness
Regular practice with this formula sheet improves calculation accuracy and problem-solving skills. Additionally, students gain confidence for CBSE and ICSE exams.
Chapter : Probability
This chapter introduces the mathematics of chance. You’ll learn how to measure how likely an event is to occur, from impossible (0) to certain (1).
“`1. Basic Definitions
- Experiment
- An action that leads to well-defined outcomes.
- Examples: Tossing a coin, rolling a die, drawing a card.
- Random Experiment
- An experiment where all possible outcomes are known, but the exact result cannot be predicted in advance.
- Sample Space (S)
S = {Set of all possible outcomes}
- Examples:
- Coin toss: S = {Head, Tail}
- Die roll: S = {1, 2, 3, 4, 5, 6}
- Examples:
- Event (E)
E ⊆ S (Event is a subset of sample space)
- A collection of one or more outcomes.
- Examples:
- Getting an even number on die: E = {2, 4, 6}
- Getting a Head on coin: E = {Head}
- Favorable Outcomes
Outcomes that satisfy the event condition.
- Example: For event “rolling a number > 4” on die, favorable outcomes = {5, 6}.
2. Types of Probability
- Theoretical (Classical) Probability
P(E) = Number of favorable outcomes / Total number of possible outcomes = n(E) / n(S)
- P(E): Probability of event E occurring.
- n(E): Number of favorable outcomes for E.
- n(S): Total number of equally likely outcomes in sample space.
- Condition: All outcomes must be equally likely.
- Range: 0 ≤ P(E) ≤ 1
- Experimental (Empirical) Probability
P(E) = Number of trials in which event occurred / Total number of trials conducted
- Also called relative frequency.
- Based on actual experiments/observations.
- As number of trials increases, experimental probability approaches theoretical probability.
3. Important Properties and Rules
- Range of Probability
0 ≤ P(E) ≤ 1
- P(E) = 0: Impossible event (e.g., getting 7 on a standard die).
- P(E) = 1: Certain event (e.g., getting a number between 1-6 on a die).
- Complementary Events
P(E) + P(not E) = 1
P(not E) = 1 – P(E)An event that represents the non-occurrence of event E is called its complement (denoted as Ē or E’).
- Sum of Probabilities of All Elementary Events
P(E1) + P(E2) + … + P(En) = 1
4. Common Probability Examples
- Coin Toss (Fair Coin)
S = {H, T}, n(S) = 2. P(Head) = P(Tail) = 1/2
- Single Die Roll (Fair Die)
S = {1, 2, 3, 4, 5, 6}, n(S) = 6. P(Any number) = 1/6
- Deck of Cards (52 Cards)
Event Probability Drawing a Spade 13/52 = 1/4 Drawing a King 4/52 = 1/13 Drawing a Red Card 26/52 = 1/2 Drawing a Face Card 12/52 = 3/13
5. Solving Probability Problems
- Step-by-Step Method
- Identify the experiment.
- List all possible outcomes (Sample Space S).
- Identify favorable outcomes for the event E.
- Count: n(E) and n(S).
- Apply: P(E) = n(E) / n(S).
- Simplify the fraction if possible.
7. Experimental vs Theoretical Probability
- Comparison
- Theoretical: Calculated using logic/mathematics.
- Experimental: Based on actual trials/observations.
- As number of trials → ∞, experimental probability → theoretical probability.
Quick Revision Summary
- Theoretical Probability: P(E) = n(E) / n(S)
- Range: 0 ≤ P(E) ≤ 1
- Impossible Event: P(E) = 0 | Certain Event: P(E) = 1
- Complementary: P(E) + P(Ē) = 1
- Fair Coin: P(H) = 1/2 | Fair Die: P(any number) = 1/6
- Deck of Cards: Total = 52, Suits = 4, Face Cards = 12
Frequently Asked Questions (FAQ’s)
- What topics are covered in the Class 9 Maths Formulas PDF?
The Class 9 Maths Formulas PDF includes formulas for all chapters, such as Algebra, Geometry, and Statistics. Moreover, it helps students revise effectively and practice exam-oriented questions. - How can students use the Number System Class 9 Formula PDF effectively?
The Number System Class 9 Formula PDF allows students to solve questions systematically. Furthermore, repeated practice with this PDF improves speed, accuracy, and exam confidence. - Why is Class 9 Maths Number System Formulas PDF important for practice?
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Yes, Coordinate Geometry Class 9 Formulas PDF simplifies problem-solving. Additionally, it includes formulas for slopes, distances, and midpoints. Therefore, students practice systematically before exams. - Why should learners use Class 9 Maths Coordinate Geometry Formula Sheet PDF?
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Euclid’s Geometry Class 9 Formulas PDF presents important theorems clearly. Moreover, students can revise the logic behind proofs effectively before exams. - How does Class 9 Maths Chapter 5 Euclid’s Geometry Formulas PDF help students?
It summarizes key postulates, axioms, and theorems. Furthermore, quick reference ensures better conceptual clarity and exam readiness. - What does Lines and Angles Class 9 Formulas PDF include?
This PDF contains all essential angle relationships, parallel line theorems, and proofs. Moreover, regular practice improves problem-solving and strengthens geometry skills. - How is Class 9 Maths Lines and Angles Formula Sheet useful for revision?
The sheet organizes formulas chapter-wise. Moreover, it supports last-minute revision and helps students recall key concepts efficiently. - Why use Triangles Formulas Class 9 PDF for exams?
Triangles Formulas Class 9 PDF provides formulas for area, similarity, and Pythagoras theorem. Moreover, it improves speed and accuracy during exam practice. - What are the advantages of Class 9 Maths Triangles All Formulas PDF?
This PDF compiles all triangle formulas in one place. Additionally, students can revise quickly and solve questions more confidently before exams. - How can Quadrilaterals Class 9 Formulas PDF help in concept understanding?
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The PDF includes area and perimeter formulas for various shapes. Additionally, students can solve practical questions quickly and revise effectively before tests. - How is Class 9 Maths Areas of Parallelograms and Triangles Formula Sheet PDF helpful?
It provides a consolidated list of formulas for easy reference. Moreover, repeated practice improves accuracy and exam confidence. - Can Circles Formulas Class 9 PDF support problem-solving in exams?
Yes, Circles Formulas Class 9 PDF provides radius, chord, and area formulas. Moreover, consistent practice ensures students handle all circle-based questions efficiently.

