Question

The length of the minute hand of a clock is 21 cm. The area swept by the minute hand in 10 minutes is

(a) $231c{m}^2$ (b) $210c{m}^2$ (c) $126c{m}^2$ (d) $252c{m}^2$

Answer 1

Area of the sector = $\frac{{60}^o}{{360}^o}\times \pi \times r^2$

Take the length of the minute hand as the radius = 21 cm

If 60 minutes make 360 degrees, 10 minutes would make 60 degrees.
$\frac{{60}^o}{{360}^o}\times \pi \times {21}^2=231$