Question

A park is in the form of a rectangle 120 m $\times$ 100 m. At the centre of the park there is a circular lawn. The area of the park excluding lawn is 8700 m${}^2$. Find the radius of the circular lawn.

Answer 1

Area of the park = $(120\times 100)=12000$ $m^2$

Area of the park excluding the lawn = $8700$ $m^2$

Therefore, area of the circular lawn = $(12000-8700)$ $m^2$

$\pi r^2=3300$

$r^2=3300\times \frac{7}{22}=150\times 7$

$r=32.4$ $m$