Question

The radius of a semicircle is 1 kilometer. what is the semicircle's perimeter? use 3.14 for pie.

Answer 1

5.14 km

Explanation:

A semicircle is 1/2 of a circle so the perimeter is just 1/2 of the circumference

C = 2 * pi r for a circle so for a semicircle

1/2* 2* pi *r

pi*r

3.14 * 1

3.14

If we want to include the piece that closes the semicircle, we need to add the diameter

d = 2r = 2(1) = 2

2+3.14 = 5.14