Question

Find the area of a circular ring made by two concentric circles of radii 7cm and 10.5cm . Plz give correct answer in step by step explanation plz.....

Answer 1

Given ,

• The radii of two concentric circle are 7 cm and 10.5 cm

According to the question ,

$\boxed{ \sf{Area \: of \: circular \: ring = Difference \: of \: areas \: of \: two \: concentric \: circle}}$

Thus ,

$\sf \mapsto Area \: of \: ring = \frac{22}{7} \{{(10.5)}^{2} - {(7)}^{2} \} \\ \\ \sf \mapsto Area \: of \: ring = \frac{22}{7} \times (110.25 - 49) \\ \\\sf \mapsto Area \: of \: ring = \frac{22 \times 61.25}{7} \\ \\\sf \mapsto Area \: of \: ring = \frac{13.47}{7} \\ \\\sf \mapsto Area \: of \: ring = 192.5 \: \: {cm}^{2}$

Therefore , the area of circular ring is 192.5 cm²