Answer: 39.25
========================================
Work Shown:
d = diameter = 10
r = radius = d/2 = 10/2 = 5
A = area of a full circle
A = pi*r^2 = 3.14*5^2 = 78.5
Cut this in half to get the area of a semicircle (aka half circle)
(78.5)/2 = 39.25
This result is approximate.
