The length of the minute hand of a wall clock is 7 cm. How much area does it sweep in 20 minutes?
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Sorry for the bad handwriting. Hope this helps
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samikksha123:
i have an doubt pls clear me mate y do u divide 360 by 3
A full revolution of the minute hand is 60 minutes. In 20 minutes it makes 20/60 =1/3 revolution. As one full revolution makes 360°, 1/3 revolution makes 1/3 × 360°
hence 360/3
thnx mate
np
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60 min = 1 revolution by minute hand
so 1 min = 1/60 revolution
20 min= 1/60 × 20 = 1/3 revolution
1 revolution = 1 circle area
1/3 revolution = 1/3 circle area
hence area formed in 20 minutes by minute hand = 1/3 PI R ^2
= 1/3 × 22/7 × 7 × 7 = 154/3 cm^2
so 1 min = 1/60 revolution
20 min= 1/60 × 20 = 1/3 revolution
1 revolution = 1 circle area
1/3 revolution = 1/3 circle area
hence area formed in 20 minutes by minute hand = 1/3 PI R ^2
= 1/3 × 22/7 × 7 × 7 = 154/3 cm^2
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