Question

The length of a chain used as the boundary of a semicircular park is 108 m. Find the area of the park.

Answer 1

Length of the boundary of the semicircular park = 108 m

⇒$\pi r+2r=108$

⇒ $r(\frac{22}{7}+2)=108$

⇒$r=\frac{108\times 7}{36}$

⇒ $r=21m$

Area of the semicircular park$=\frac{1}{2}\pi r^2$

= $\frac{1}{2}\times \frac{22}{7}\times 21\times 21$

= $693m^2$