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 of turfing the plot at Rs. 1.25 per square metre. (Take $\pi =3.14$)

Answer 1

4 x area of semicircle x 1.25 ( r = $\frac{40}{2}$ = 20m)

= 4 x $\frac{\pi r^2}{2}$ x 1.25

= 2 x 3.14 x 20 x 20 x 1.25

= Rs 3140

if pie value is $\frac{22}{7}$ , then the answer will be Rs 3142.85