Example 1 · level 1
A wooden box is 18 cm long, 5 cm wide and 8 cm high. Find its total surface area (in cm²).
Show solution
- TSA = 2(90 + 40 + 144) = 548 cm².
Answer: 548
SSC & BANK EXAMS: QUANTITATIVE APTITUDE · MENSURATION
Mensuration 3D: volume and surface area
Cuboid V = lbh. Cylinder V = πr²h, CSA = 2πrh. Cone V = ⅓πr²h. Sphere V = 4/3 πr³ (π = 22/7).
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Worked examples
Example 2 · level 2
A cylindrical water tank in a village has radius 21 m and height 18 m. Find its volume (in m³). (π = 22/7)
Show solution
- V = 22/7 × 21² × 18 = 24,948 m³.
Answer: 24,948
Example 3 · level 3
Find the volume (in cm³) of a metal ball of radius 21 cm. (π = 22/7, answer to 2 decimal places if needed)
Show solution
- V = 4/3 × 22/7 × 9261
- = 38,808 cm³.
Answer: 38,808