Choose a Calculation:
Given r1 and r2 find c1, c2 and a0 Given c1 and c2 find r1, r2 and a0 Given r1 and c2 find r2, c1 and a0 Given r2 and c1 find r1, c2 and a0 Given a0 and r1 find c1, c2 and r2 Given a0 and r2 find c1, c2 and r1 Given a0 and c1 find r1, r2 and c2 Given a0 and c2 find r1, r2 and c1

r1 =    r2 =  Units:     meters feet inches     c1 =  c2 =  a0 =

r1 = outer radius r2 = inner radius a0 = shaded area a1 = area of circle of r1 a2 = area of circle of r2 c1 = outer circumference c2 = inner circumference Π = Pi