Since the diameter of the circle is 5ft, the perimeter of the full circle would be 5 times pi feet, or about 15.7 ft. However, since we're only look at a half circle, the perimeter of the half circle is half that or about 7.85 feet. The other part of the perimeter is the diameter itself, so we add 5ft, to get a total of 12.85 feet.
