Question

The length of a rope by which a horse must be tethered so that it may be allowed to graze over an area of 154 sq meter is

Answer 1

area of circle =

$\pi {r}^{2}$

$r \: refers \: to \: radius \\ 154 = \frac{22}{7} \times {r}^{2} \\ 154 \times \frac{7}{22} = {r}^{2} \\ 7 \times 7 = {r }^{2} \\ 49 = {r}^{2} \\ \sqrt{49} = {r}^{2} \\ 7 = r$

length of rope which a horse must be tethered must be 7 m as radius of circle is equal to length of rope