Question

If the perimeter of a semi-circular protractor is 36 cm, find the diameter of the protractor.

Answer 1

let radius of the protractor = r cm
perimeter of the semicircle = pi*r+2r=36 cm

r(pi+2)=36
r(22/7+2)=36
r(36/7)=36
r= 36×(7/36)
r=7 cm
Therefore
diameter of the protractor = 2r
=2×7
=14cm

Answer 2

let the diameter of the semicircular protracter be d
now
perimeter = 36
(22/7 x d/2) +d = 36
11d/7 + d = 36d
(11d + 7d)/7 = 36
18d/ 7= 36
d= 14
therefore
the diameter = 14 cm