STONE-GROUND FLOUR
The radius of a milestone is 3 meters greater than the radius of another, and their areas differ by 15pi square meters. Find the radius of the larger milestone.
If the larger radius is r, then we have
πr^2 = π(r-3)^2 + 15π
r^2 = r^2-6r+9 + 15
6r = 24
r = 4
check:
16π = π + 15π