Quantitative Aptitude – Mensuration
Master formulas and techniques for calculating area, volume, surface area, and perimeter of 2D and 3D geometric shapes.
1. 2D Figures
- Rectangle: Area = l × b, Perimeter = 2(l + b)
- Square: Area = a², Perimeter = 4a
- Circle: Area = πr², Circumference = 2πr
- Triangle: Area = ½ × base × height
- Parallelogram: Area = base × height
- Trapezium: Area = ½ × (a + b) × height
2. 3D Figures
- Cuboid: Volume = l × b × h, TSA = 2(lb + bh + hl)
- Cube: Volume = a³, TSA = 6a²
- Cylinder: Volume = πr²h, CSA = 2πrh, TSA = 2πr(h + r)
- Sphere: Volume = (4/3)πr³, Surface Area = 4πr²
- Cone: Volume = (1/3)πr²h, CSA = πrl, TSA = πr(l + r)
- Hemisphere: Volume = (2/3)πr³, CSA = 2πr², TSA = 3πr²
3. Conversion Units
- 1 m² = 10,000 cm²
- 1 m³ = 1,000,000 cm³
4. Strategy
- Memorize key formulas.
- Use correct unit conversions in composite figures.
Summary: Mensuration involves geometric calculation using formula-based reasoning. Accuracy depends on correct substitution and unit discipline.