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If the perimeter of a semi-circular protractor is 36 cm. Find its diameter.

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#### Solution

Let r cm be the radius of the protractor, then

Perimeter = πr + 2r

According to the question,

⇒ 36 = πr + 2r

⇒ 36 = r `( 22/7 + 2)`

⇒ r = 7 cm.

∴ The diameter of the protractor is ( 2 x 7) cm = 14 cm.

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