Q23 of 157 Page 846

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

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