Question

Find the area of the shaded region in given figures

Answer 1

$d+d=42$cm $\Rightarrow$ $d=21cm$ Area of shaded region = Area of circle - Area of small circle

$r=10.5$cm $=\pi (R^2-r^2)$

Hence area $=2\times$ area of circle $=\frac{22}{7}({10.5}^2-{5.25}^2)$

$=2\times \pi r^2$ $=2259.875{cm}^2$

$=2\times \frac{22}{7}\times 10.5\times 10.5$

$=693{cm}^2$