Question

find the area of the shaded region .....​

Answer 1

Step-by-step explanation:

shaded area = total area - unshaded area

= π (R²-r²)

= 22/7 (21²- 21²/4) ×1/4

=22/7 × 21² (1-1/4)×1/4

= 22×21×3×3/16

= 259.875m²

Answer 2

Step-by-step explanation:

The given figure can be assumed as a complete circle of diameter 21m and two semicircles of diameter 10.5m removed from it

So area of shaded region will be

= Area of circle with diameter 21 m -2×Area of semicircles with diameter 10.5 m

Now converting the diameters into radius

r1=21/2=10.5m

r2=10.5/2= 5.25 m

So area of shaded region

$= \pi {r1}^{2} - 2 \times \frac{\pi {r2}^{2} }{2}$

$= \pi \times 10.5 \times 10.5 - \pi \times 5.25 \times 5.25$

$= 82.6875\pi$

This will be the area of shaded region