Two concentric circles of radii 18 and 16 cm are drawn on a paper. What is the area of the portion that is inside the outer circle but outside the inner circle?
68π sq. cm.
136π sq. m.
4624π sq. m.
34π sq. m.
The required area is difference of the areas of the two circles. π($18^2 - 16^2$) = 68π sq. cm.