Question

Area of a circular field is 3850 $c{m}^2$. What is the perimeter of that field?
$(Take\pi =\frac{22}{7})$

• A. 385 cm
• B. 192.5 cm
• C. 150 cm
• D. 220 cm

Answer 1

The correct option is D

220 cm

Area of the circular field $=\pi r^2=3850c{m}^2$
(where r is the radius of the field)

$\Rightarrow \frac{22}{7}\times r^2=3850$

$\Rightarrow r^2=\frac{3850\times 7}{22}$

$\Rightarrow r^2=1225$

$\Rightarrow r=\pm 35$

Here, radius of the field cannot be negative.

$\therefore r=35\text{cm}$

Perimeter of the field
$=2\pi r=2\times \frac{22}{7}\times 35=220cm$