Question

Here is a semicircle of radius x

Answer 1

Explanation:

Perimeter of semicircle

= Diameter + Arc of semicircle

= 2x + 0.5(π2x)

= πx + 2x. (C)

When πx + 2x = 25.71 cm,

we have x(π + 2) = 25.71cm.

=> x = 25.71 / (3.142 + 2) = 5.

Hence the radius x is 5cm.