Question:
The perimeter of a circular field is 242 m. The area of the field is
(a) 9317 m2
(b) 18634 m2
(c) 4658.5 m2
(d) none of these
Solution:
(c) 4658.5 m2
Let the radius be r m.
We know:
Perimeter of a circle $=2 \pi r$
Thus, we have:
$2 \pi r=242$
$\Rightarrow 2 \times \frac{22}{7} \times r=242$
$\Rightarrow \frac{44}{7} \times r=242$
$\Rightarrow r=\left(242 \times \frac{7}{44}\right)$
$\Rightarrow r=\frac{77}{2}$
$\therefore$ Area of the circle $=\pi r^{2}$
$=\left(\frac{22}{7} \times \frac{77}{2} \times \frac{77}{2}\right) \mathrm{m}^{2}$
$=4658.5 \mathrm{~m}^{2}$
Click here to get exam-ready with eSaral
For making your preparation journey smoother of JEE, NEET and Class 8 to 10, grab our app now.