Question

A square water tank has its side equal to 40 m. There are four semi-circular grassy plots all round it. Find the cost turfing the plot at Rs. 1.25 per square metre (Take $\pi$ = 3.14).

Answer 1

Given,

Side of a Square water tank $=40m$

Radius of a semicircular plot(r) = Side of a Square/2 $=\frac{40}{2}=20cm$

Area of 1 semi circular grassy plot $=\pi \frac{r^2}{2}$$=\pi \frac{{20}^2}{2}=200\pi c{m}^2$

Area of 4 semi circular grassy plots $=4\times 200\pi =800\pi c{m}^2$

Rate of turfing the plot $=1.25$ per square meter

Cost of turfing the plot = Area of 4 semi-circular grassy plots $\times$ Rate of turfing the plot

Cost of turfing the plot $=800\pi \times 1.25=800\times 3.14\times 1.25=3140$

Hence, the Cost of turfing the plot is $Rs.3140$