Question

A park is in the shape of a semicircle with radius $21$ m. Find the cost of fencing it at the cost of Rs. $5$ per metre.

Answer 1

Fencing is done around the circumference of park and diameter.

Therefore, total length of fencing $=\pi r+d$

$=\frac{22}{7}\times 21+42$

$=108m$

Cost of fencing $=Rs.(5\times 108)=Rs.540$