Question

In Fig., $OACB$ is a quadrant of a circle with centre $O$ and radius $3.5cm$. If $OD=2cm$, find the area of the
(i) quadrant $OACB$, (ii) Shaded region

Answer 1

(i)

Area of quadrant $OACB=\frac{\text{Area of Circle}}{4}=\frac{\pi \times r^2}{4}=\frac{1}{4}\times \frac{22}{7}\times 3.5\times 3.5$ $=9.625c{m}^2$
(ii)
Area of the shaded region $=$ Area of Quadrant $-$Area of $△BDO$

$=9.625-(\frac{1}{2}\times 3.5\times 2)$

$=6.125c{m}^2$