The semicircle below has a diameter of 20. Find the area of the blue region.
PICTURE OF DIAGRAM: https://latex.artofproblemsolving.com/7/1/a/71ae2177f4006b219d91ff9de0939073a0a0b766.png
The blue area = area of semi-circle - area of right triangle
Area of semi-circle = (1/2) pi (radius)^2 = (1/2) pi (10)^2 = 50 pi
Area of right triangle = (1/2) (product of the legs) = (1/2) (12 * 16) = 96
Blue Region = 50pi - 96 ≈ 61.08
+4 
