Area of a circle — Mensuration Aptitude Question
Area of a circle: What is the area of a circle with radius 14 cm? (Take π = 22/7.) Answer and worked solution on CodeKairo.
- Topic: Mensuration
- Section: Quantitative Aptitude
- Difficulty: Easy
- Time target: 50 seconds
Question
What is the area of a circle with radius 14 cm? (Take π = 22/7.)
Options
- 308 cm²
- 462 cm²
- 616 cm²
- 704 cm²
Show the answer and the worked solution
Correct answer: C. 616 cm²
Worked solution
- Area = (22/7) × 14 × 14 = 22 × 2 × 14 = 616 cm².
Answer: 616 cm².
The idea
Cancel the 7 in π = 22/7 against the radius before multiplying. Radii that are multiples of 7 always work out to whole numbers.
Shortcut. Remember r = 7 → 154 cm²; doubling the radius to 14 quadruples the area: 4 × 154 = 616.
Common trap. 308 cm² — cancelling 14 against the 7 in 22/7 but dropping the resulting 2, so 22 × 14 instead of 22 × 2 × 14.