Question

A circular grassy plot of land 21m in radius, has a path 2.1 m wide running round it on the outside. Find the
cost of gravelling the path at 150 per m2.​

Answer 1

The cost of gravelling the path at Rs. 150 per m² is Rs. 43659

Step-by-step explanation:

Given that, the radius of the circular grassy plot is 21 m

Then the area of the grassy plot is

= π * 21² m²

= 22/7 * 21 * 21 m²

= 1386 m²

Also given that, the width of the path running round it is 2.1 m

Then radius of circular plot along with the path is

= (21 + 2.1) m

= 23.1 m

So the area of the circular plot along with the path is

= π * 23.1² m²

= 22/7 * 23.1 * 23.1 m²

= 1677.06 m²

Therefore the area of the path is

= (1677.06 - 1386) m²

= 291.06 m²

and thus the cost of gravelling the path at Rs. 150 per m² is

= Rs. (150 * 291.06)

= Rs. 43659