Question

A piece of wire 144 cm long is bent to form a semicircle as shown in the figure. Find the diameter of the semicircle, giving your answer in meters ( Take pi to be 22/7.)

Answer 1

Circumference= 2πr

For a semi circle, C= 2πr/2

144= (2×22×r)÷(7×2)

144= (44r)÷(14)

cross multiply:

44r= 144×14

44r= 2016

divide both sides by 44

r= 2016÷44

r=45.8cm. But d=2r

d= 2×45.8

d=91.6cm approximately 92cm

Thus, diameter= 92cm