Question

Find the area of the shaded region.

• A. $11,700m^2$
• B. $11,604m^2$
• C. $11,704m^2$
• D. $11,500m^2$

Answer 1

The correct option is C

$11,704m^2$

Area of the ring = $\pi (R^2-r^2)$

Here, R = 140m, r = 126m

$\therefore$ Area = $\pi ({140}^2-{126}^2)$

= $\pi (140+126)(140-126)$ $[\because a^2-b^2=(a+b\left)\right(a-b\left)\right]$

= $\frac{22}{7}\left(266\right)\left(14\right)$

= $22\times 266\times 2$

= $11,704m^2$