Question

Two circles are drawn inside a big circle with the diameters 3/5 and 1/5 of the diameter
of the big circle. Find the area of the shaded portion, if the length of the diameter of
the big circle is 20 cm.

Answer 1

Answer:

A = πr2 = π(8)2 = 81π cm2 Let d1 = (2/3) × 18 = 12 cm r1 = 6 cm Area of the circle, A1 = πr2 = π(6)2 = 36π cm2 d2 = (1/3) × 18 = 6 cm r2 = 3 cm Area of the circle, A2 = πr2 = π(3)2 = 9π cm2 Area of the shaded portion = A – (A1 + A2) Area of the shaded portion = 81π – (36π – 9π) = 36π cm2