Question

if the perimeter of a semi-circular park is72metre.find its area and radius

Answer 1

Perimeter of semi circular park= 72 m
$\\r(\pi + 2) = 72 \\ r( \frac{22}{7} + 2) = 72 \\ r( \frac{22 + 14}{7} ) = 72 \\ r( \frac{36}{7} ) = 72 \\ r = 72 \times \frac{7}{36} \\ r = 14$
$area \: ofsemi \: circle = \frac{1}{2} \times \pi {r}^{2} \\ = \frac{1}{2} \times \frac{22}{7} \times {14}^{2} \\ = \frac{11}{7} \times 196 \\ = 11 \times 28 \\ = 308$