Answer:
102.8 cm
Step-by-step explanation:
The perimeter of a semicircle is the sum of the length of the diameter and the length of the curved edge. The curved edge is half the circumference of a circle with the same radius.
perimeter = diameter + curved edge
= 2r +1/2(2πr) = r(2 +π)
= (20 cm)(2 +π) ≈ 102.8 cm
The perimeter of the window is about 102.8 cm.
