posted by Randy .
the inner circumference of a ring is 1.2pi cm. the outer circumference of the ring is 2pi cm. find the area of the region bounded by the outer and inner circumference.
The two radii are 0.6 and 1 cm.
The area of the bounded region is thus
pi[1^2 - 0.6^2] = 0.64*pi cm^2