Class 8 Mathematics Complete Formula Bank

Algebraic Identities, Mensuration (2D & 3D), and Linear Equations formulas for Class 8.

Class 8 Mathematics 2 Chapters Covered 4 Master Formulas IIT-JEE & NEET Foundation
Chapter 1

Algebraic Identities

Standard Algebraic Identities

(a + b)² = a² + 2ab + b² | (a - b)² = a² - 2ab + b² | (a + b)(a - b) = a² - b²

Essential formulas for factorization and instant quadratic expansion.

Variables: a, b are real numbers or algebraic expressions
Exam Tip: Difference of squares (a² - b² = (a+b)(a-b)) is the single most tested identity in Olympiads.

Product Identity with Common Term

(x + a)(x + b) = x² + (a + b)x + ab

Foundation for middle-term splitting in quadratic factorizations.

Variables: x is variable, a and b are constants
Exam Tip: If signs are negative: (x - a)(x - b) = x² - (a + b)x + ab.
Chapter 2

Mensuration (2D & 3D)

Trapezium & Rhombus Area

SI: m² or cm²
Area of Trapezium = 1/2 × (a + b) × h | Area of Rhombus = 1/2 × d1 × d2

Diagonals of a rhombus bisect each other at right angles (90°).

Variables: a, b = parallel sides, h = perpendicular distance; d1, d2 = diagonals
Exam Tip: Side of rhombus s = √((d1/2)² + (d2/2)²) via Pythagoras theorem.

Cuboid & Cylinder 3D Formulas

SI: Volume: m³, Surface Area: m²
Cuboid Volume = l × b × h, Total Surface Area = 2(lb + bh + hl) | Cylinder Volume = πr²h, CSA = 2πrh, TSA = 2πr(r + h)

CSA is curved surface only; TSA includes both circular top and bottom flat bases.

Variables: l=length, b=breadth, h=height, r=radius
Exam Tip: Diagonal of cuboid = √(l² + b² + h²). Maximum length of rod that can fit in a room.