How do you figure the perimeter of a semicircle if the the straight side is 36?

Consider the straight side as the diameter of a circle, find the circumference of the circle, calculate half the circumference and then add it to the diameter.

circumference = pi x diameter = 3.14 x 36 = 113.04

perimeter of semicircle = 1/2 circumference + 36 = 56.52 + 36 = 92.52