What is the radius of a sphere whose surface area is 100 square meters
SA =4 x Pi x r^2, r=radius
100 = 4 x 3.141592 x r^2
100 = 12.566368 x r^2 divide both sides by 12.566368
7.95775 = r^2 take the square root of both sides
r = 2.82 meters
