Question

Find the area and perimeter of the following semicircles: Radius = 1.4cm

Answer 1

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 Area of a Semi-circle with radius 1.4cm

= `pi(1.4)^2/(2)`

= `(22)/(7) xx (1.4)^2/(2)`
= 3.08cm²
The Perimeter of a Semi-circle with radius r
= π(1.4) + 2 x 1.4
= 1.4(π + 2)

= `14(22/7 + 2)`

= `(36)/(7) xx 1.4`
= 7.2cm.