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Question
The length of the minute hand of a clock is 21 cm. The area swept by the minute hand in 10 minutes is
Options
231 cm2
210 cm2
126 cm2
252 cm2
Solution
Angle subtends by the minute hand in 1 minute = 6∘
∴ Angle subtends by the minute hand in 10 minutes = 60∘
Now,
Area of the sector`=theta/(360°) pi"r"^2 = 60°/360° xx 22/7(21)^2 = 231 "cm"^2`
Now,
Area of the sector`=theta/360°pi"r"^2 = (60°)/360^circxx22/7(21)^2=231 "cm"^2`
Hence, the correct answer is option (a).
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