Question

If the perimeter of a semi-circular protractor is 88 cm.find the diameter of the protractor.​

Answer 1

perimeter = pi*r = 88 (semicircular)

diameter = 2*r = d

∴ pi * r = 88

r = 88/pi = 88 * 7 / 22

              = 4 * 7

              = 28 cm

∴ d = 2 * 28

d =  56 cm

Answer 2

Perimeter of a semi circle =

$\pi \: \times radius$

=> 88 c.m = π * radius

radius=

radius =

$88 \div \pi$

28 c.m radius

diameter = 2*radius = 56 c.m