Question

A circular pond is 17.5 m in diameter. It is surrounded by a 2 m wide path. Find the cost of constructing the path at the rate of Rs. 25 per $m^2$.

Answer 1

Radius of the pond, $r=\frac{17.5}{2}=8.75cm$

Width of the path $=2m$

So, raidus of outer circle = 8.75 + 2 = 10.75 m

Now, area of the path $=\pi \times {10.75}^2-\pi \times {8.75}^2=122.5m^2$

So, cost of constructing the path =122.5 $\times$ 25 = Rs. 3062.5