Question

Circular footpath of width 2 metres is constructed at the rate of Rs 20 per square metre, around a circular park of radius 1500m. Find the total cost of construction of the footpath.

Answer 1

= Area of footpath = Area of outer circle - Area of inner circle
$=\pi (1500+2{)}^2-\pi (1500{)}^2$
$=\pi (1500+2{)}^2-(1500{)}^2$
$=\pi 2\left(3002\right)=\frac{22}{7}\times 2\times 3002$
$18869.71sq.m$
Total cost of construction $18869.71\times 20$
Rs. 3,77,394.30