The length of the minute hand of a clock is 21 cm. The area swept by the minute hand in 10 minutes is
Length of the minute hand of a clock = 21 cm
∴ Radius = R = 21 cm
In 1 minute, minute hand sweeps 6°
So, in 10 minutes, minute hand will sweep 10 × 6° = 60°
Area swept by minute hand in 10 minutes = Area of a sector of angle 
of a circle with radius R = 
= 22/7 × 21 × 21 × 60/360 = 231 cm2
23