Question

What is the approximate distance around the half circle with radius 12 centimeters?

Answer 1

You can find the perimeter of a circle by using the radius.
circumference = 2 $\pi r$
Circumference = 2 $\pi x 12$
circumference = 24 pi
Since you are only trying to find half of the circle you would divide your answer by 2 

24pi / 2 = 12 pi

12 pi = 37.68

The answer is B. 37.7