Question

if the perimeter of a semi circular protractor is 36cm find the it's diameter

Answer 1

In this question,pie×r=36m
so,r=36×7/22=126/11cm
So,diameter=126/11×2=22.9cm

Answer 2

this is the required solution.

perimeter of the protactor      =diameter+semi arc
                  36                         = 2r  + πr
⇒                   36                        = r(2+π)
⇒                  36/(2+π)               = r
⇒                  36/(2+22/7)           =r
⇒                  36*7/(14+22)         =r
⇒                   252/36                  =r
                  ∴r = 7
therefore, diameter=2r=14 cm