Question

Find the area of the ring if outer radius is 10 cm and inner radius is 5 cm. Solve

Answer 1

area of ring with inner radius = πr^2 = 25πcm^2
area of ring with outer radius = πR^2 = 100πcm^2
area of ring = area of ring with(outer-inner)radius = 100π - 25π = 75π cm^2
Ans. 75 × 22/7 = 235.71 cm^2