Question

If the perimeter of a semi-circular protractor is 66 cm, find the diameter of the protractor (Take π = 22/7).

Answer 1

Let the radius of the protractor be r cm. Then,
Perimeter = 66 cm

⇒ 1/2(2 πr) = 66

∵ `[`

⇒ πr = 66

⇒ \frac { 22 }{ 7 } × r = 66

⇒ r = 21 cm

∴ Diameter of the protractor = 2r = (2 × 21) cm

= 42 cm