Question

AB and CD are perpendicular to each other.

OA = 7 cm and OD is diameter of smaller circle.

Find the area of shaded part.​

Answer 1

area of shaded circle is πr²

r=diametre/2

diametre=7

r=3.5

area of shaded circle=

$\frac{22}{7} \times 4.5 \times 4.5 \\ = 63.61 \: app. {cm}^{2}$

area of semi circle is

$\frac{\pi \times {r}^{2} }{2}$

$\frac{\pi \times {4.5}^{2} }{2}$

=>31.80cm²

area of triangle with shaded part =½*b*h

b=diametre

h=radii

therefore,

$\frac{1}{2} \times 7 \times 4.5 \\ = 15.75 {cm}^{2}$

area of shaded part in the semi circle =total area of semi circle -area of triangle

=>31.80-15.75

=>16.05cm²

area of total shaded region =area of shaded circle + area of shaded part with triangle

63.61+16.05

79.66 cm²