Question

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

विकल्प

• 231 cm² 

• 210 cm² 

• 126 cm²

• 252 cm²

Answer 1

The length of the minute hand of a clock is 21 cm. The area swept by the minute hand in 10 minutes is 231 cm² .

Explanation:

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).