Question

A circular grassy plot of land of diameter 42 metre has a path wide 3.5 m running around it on outside find the cost of gravelling the path ₹ 4 per square metre

Answer 1

₹ 2,001.20

Explanation:

We can consider the grassy plot as a circle with radius = 42/2 = 21 m

The grassy plot and the path together form another circle with radius = 21 + 3.5 = 24.5 m

Area of a circle = πr² where r is the radius

Area of grassy plot = π x 21² = 441π m²

Area of outer circle (grassy plot + path) = π x (24.5)² = 600.25π m²

Area of the outer path alone = 600.25π - 441π = 159.25π = 500.30 sq meters

Cost of paving 1 square meter = ₹ 4

Cost of paving 500.3 sq m = 500.3 x 4 = ₹ 2,001.20