Question

The area of circular playground is 22176 m² . Find the cost of fencing this ground at the rate of ₹ 50 per metre.

Answer 1

Area of circular playground = 22176 m²
$$\begin{gathered} \Rightarrow {\mathrm{\pi r}}^2=22176 \\ \Rightarrow \frac{22}{7}{\mathrm{r}}^2=22176 \\ \Rightarrow {\mathrm{r}}^2=\frac{22176\times 7}{22} \\ \Rightarrow {\mathrm{r}}^2=7056 \\ \Rightarrow \mathrm{r}=84\mathrm{cm} \end{gathered}$$
circumference = $2\mathrm{\pi r}=2\times \frac{22}{7}\times 84=528{\mathrm{cm}}^2$
Cost of fencing the ground = $528\times 50=Rs26400$