2026 · Q60
The minute hand of a clock is 15 cm long and sweeps an area of 15π cm² on the dial of the clock. How much angle does it describe during this period?
Elementary MathematicsMensuration
- A12°
- B18°
- C24°
- D30°
Explanation
The swept sector satisfies (θ/360°)·π·15²=15π, so θ=15×360/225=24°, option C. Equivalently, 15π cm² is 1/15 of the full dial area 225π cm², hence 1/15 of 360°. Reading the area as a fraction of an hour instead gives nonsense.