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Question
Find the area and perimeter of the following semi-circle :
Diameter= 7 cm
Solution
Diameter= 2r
`=> "r" = "diameter"/2 = 7/2` = 3.5 cm
Area of the semi-circle = `1/2 pi "r"^2`
`= 1/2 xx 22/7 xx 3.5 xx 3.5`
= 19.25 cm2
Perimeter of the semi-circle = (πr + 2r)
`= (22/7 xx 3.5) + (2 xx 3.5)`
= 18 cm
Therefore, Area= 19.25 cm2 and Perimeter= 18 cm
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