Question

Find the area and perimeter of the following semicircles: Diameter = 5.6cm

Answer 1

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.