Question

In the given figure, OABC is a quadrant of a circle with centre O and radius 3.5 cm. If OD = 2 cm, find the area of thet shaded region.

Answer 1

Area of the right-angled $△COD=\frac{1}{2}\times b\times h=\frac{1}{2}\times 3.5\times 2=3.5c{m}^2$

Area of the sector $AOC=\frac{\theta }{{360}^o}\times \pi r^2=\frac{{90}^o}{{360}^o}\times \frac{22}{7}\times (3.5{)}^2=9.625c{m}^2$

Area of the shaded region = Area of the $△$COD - Area of the sector AOC $=9.625-3.50=6.125c{m}^2$