Question

if the perimeter of a semicircular park is 72 m,find it area and radius

Answer 1

Perimeter of semi circle = pi *r + 2r

=> pi *r + 2r = 72

=> 22r/7 + 2r = 72

=> (22r+14r) / 7 = 72

=> 36r/7 = 72

=> r = 72 * 7 / 36

=> r = 2 * 7

=> r = 14 m

Area = pi *r^2 / 2

= 22 * 14 * 14 / 7*2

= 22 * 14 * 2/2

= 44 * 14 / 2

= 616 /2

= 308 m^2

Answer 2

Perimeter or circumference of a circle =( 2×72)m = 144m

circumference = 144m
2 pie R = 144m
2 R = 144 ÷ 22/7
R = 144 ÷ 22/7 ÷2

= 252/11

Area = Pie R^2
= 22/7 × (252/11 )^2
= 18144/11 m^2