Class 9 Maths Formulas Handbook (Chapter-wise)

A quick-reference, chapter-wise formula and key-facts handbook for Class 9 Mathematics (Ganita Manjari Part 1, 2026-27), covering all 8 published chapters. This Class 9 Maths formulas handbook is a handy quick-revision tool alongside the chapter-wise notes and important questions.

Chapter 1: Orienting Yourself: The Use of Coordinates

• Cartesian plane: x-axis + y-axis, 4 quadrants.
• QI(+,+), QII(−,+), QIII(−,−), QIV(+,−).
• Point = (abscissa, ordinate).

Chapter 2: Introduction to Linear Polynomials

• Linear polynomial: ax+b (degree 1); unique zero x=−b/a.
• Graph of linear polynomial = straight line.

Chapter 3: The World of Numbers

• Rational: p/q form; Irrational: non-terminating, non-repeating.
• Exponent laws: a^m×aⁿ=a^m+n; (a^m)ⁿ=a^mn.

Chapter 4: Exploring Algebraic Identities

• (a±b)² = a²±2ab+b²; a²−b²=(a+b)(a−b).
• (a±b)³ = a³±b³±3ab(a±b); a³±b³=(a±b)(a²∓ab+b²).

Chapter 5: I’m Up and Down, and Round and Round (Circles)

• Angle at centre = 2 × angle at circumference.
• Angle in semicircle = 90°.
• Cyclic quadrilateral: opposite angles sum to 180°.

Chapter 6: Measuring Space: Perimeter and Area

• Heron’s formula: Area = √[s(s−a)(s−b)(s−c)], s=(a+b+c)/2.

Chapter 7: The Mathematics of Maybe: Introduction to Probability

• P(E) = (favourable trials)/(total trials); 0≤P(E)≤1.

Chapter 8: Predicting What Comes Next?: Exploring Sequences and Progressions

• AP nth term: a_n=a+(n−1)d.
• AP sum: S_n=n/2[2a+(n−1)d].

Written by Satish

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