Question

The length of the minute hand of a clock is 21 cm. What is the area swept by the minute hand between 3: 20 and 3: 40?

• A. $456c{m}^2$
• B. $4.56c{m}^2$
• C. $2.56c{m}^2$
• D. $462c{m}^2$

Answer 1

The correct option is D

$462c{m}^2$

When the minute hand moves from 3:20 to 3:40, the angle it covers is ${120}^{\circ }$ since the minute hand moves 6° per minute

$\therefore$ Required area $=(\frac{120}{360}\times \frac{22}{7}\times 21\times 21)c{m}^2=462c{m}^2$