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Question
Find the area and perimeter of the following semicircles: Diameter = 5.6cm
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Solution
The radius of a Circle with diameter d is r = `"d"/(2)`
The Area of a Semi-circle with radius r = `(pi"r"^2)/(2)`
The Perimeter of a Semi-circle with radius r
= πr + 2r
= r(π + 2)
= `"r"(22/7 + 2)`
= `(36)/(7) xx "r"`
The radius of a Circle with diameter 5.6 is r
= `(5.6)/(2)`
= 2.8cm
The Area of a Semi-circle with radius 2.8
= `(pi(2.8)^2)/(2)`
= 12.32cm2
The Perimeter of a Semi-circle with radius r
= π x 2.8 + 2 x 2.8
= 2.8(π + 2)
= `2.8(22/7 + 2)`
= `(36)/(7) xx 2.8`
= 14.4cm.
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