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प्रश्न
The minute hand of a clock is √21 𝑐𝑚 long. Find area described by the minute hand on the face of clock between 7 am and 7:05 am
उत्तर
Radius of minute hand (r) = √21 𝑐𝑚
For 1hr = 60 min, minute hand completes one revolution = 360°
60 min = 360°
1 min = 6°
From 7 am to 7:05 am it is 5 min angle subtended = 5 × 6° = 30° = 𝜃
Area described =`theta/360^@ × pir^2`
=`30/360×22/7`× 21
=`22/4`= 5.5 cm2
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