Volume of a cone — Mensuration Aptitude Question
Volume of a cone: What is the volume of a cone with radius 7 cm and height 12 cm? (Take π = 22/7.) Answer and worked solution on CodeKairo.
- Topic: Mensuration
- Section: Quantitative Aptitude
- Difficulty: Medium
- Time target: 75 seconds
Question
What is the volume of a cone with radius 7 cm and height 12 cm? (Take π = 22/7.)
Options
- 528 cm³
- 616 cm³
- 660 cm³
- 704 cm³
Show the answer and the worked solution
Correct answer: B. 616 cm³
Worked solution
- Volume = (1/3) × (22/7) × 49 × 12 = (1/3) × 22 × 7 × 12 = 616 cm³.
Answer: 616 cm³.
The idea
A cone is one third of the cylinder on the same base and height. Forgetting the third gives 1,848 and is the standard slip.
Shortcut. A third of the height is 4, and πr² for r = 7 is 154, so the volume is 154 × 4 = 616.
Common trap. 528 cm³ — multiplying the base circumference (44) by the height, a surface-style product rather than (1/3)πr²h.