Question

If the perimeter of a semicircular protractor is 72 cm where `pi = 22/7`, then the diameter of protractor is ____________.

Options

• 14 cm

• 33 cm

• 28 cm

• 42 cm

Answer 1

If the perimeter of a semicircular protractor is 72 cm where `pi = 22/7`, then the diameter of the protractor is 14 cm.

Explanation:

`=> 72  "cm" = pi "r" + 2 "r"`

`=> 72  "cm" = "r" (pi + 2)`

`=> 72  "cm" = "r" (22/7 + 2)`

`=> 72  "cm r" ((22 + 14)/7)`

`=> 72  "cm" = "r" (36)/7`

`=> "r" = 72 xx 7/36`

`=> "r" = 14 cm`