SSC CHSL & CGL Maths Cheat Sheet

Key Definitions

• Average: Sum of values divided by the number of values. ✅

• Percentage: A fraction expressed as a part of 100. ✅

• Ratio: A comparison of two quantities. ✅

• LCM (Least Common Multiple): The smallest multiple common to two or more numbers. ✅

• HCF (Highest Common Factor): The largest factor common to two or more numbers. ✅

Important Concepts

Trigonometry

• Basic Ratios:

• sin(θ) = Opposite/Hypotenuse

• cos(θ) = Adjacent/Hypotenuse

• tan(θ) = Opposite/Adjacent

• Shortcuts:

• 30-60-90 Triangle:

• Sides: 1, √3, 2

• 45-45-90 Triangle:

• Sides: 1, 1, √2

Geometry

• Properties of Shapes:

• Triangle: Sum of angles = 180° ✅

• Circle: Area = πr² ✅; Circumference = 2πr ✅

Mensuration

• Volume and Surface Area:

• Cube: Volume = a³ ✅; SA = 6a² ✅

• Cylinder: Volume = πr²h ✅; SA = 2πr(h + r) ✅

Key Formulas

• Simple Interest:

• P: Principal

• R: Rate of interest

• T: Time (in years)

• Compound Interest:

• A: Amount

• P: Principal

• R: Rate

• T: Time

Common Mistakes to Avoid

Common Mistake: Confusing LCM with HCF; remember LCM is the smallest multiple, while HCF is the largest factor.

Memory Tricks

Tip: "SOHCAHTOA" —

• S: Sine = Opposite/Hypotenuse

• C: Cosine = Adjacent/Hypotenuse

• T: Tangent = Opposite/Adjacent

Key Diagrams

   /|
  / |  Opposite
 /  |
/___|
 Adjacent
Triangle representation

   O
  /|\
 / | \
/__|__\
 C   R
Circle representation (O = Center, R = Radius)