# If the Diameter of a Semi-circular Protractor is 14 Cm, Then Find Its Perimeter. - Mathematics

Sum

If the diameter of a semi-circular protractor is 14 cm, then find its perimeter.

#### Solution

Let AB be the diameter of the semi-circular protractor.

So, AB=14 cm

"We know that perimeter of the semicircle" = 1/2 (2pi r)+2r .........(1)

We have given the diameter of the protractor.

Therefore, radius of the protractor =14/2

So, radius of the protractor =7

Substituting the value of r in equation (1) we get,

Perimeter of the semi-circular protractor=1/2(2pxx7)+2xx7

Perimeter of the semi-circular protractor=(pixx7)+14

Substituting pi=22/7 we get

"Perimeter of the semi-circular protractor"=(22/7xx7)+14

"Perimeter of the semi-circular protractor"=22+14

"Hence Perimeter of the semi-circular protractor"'=36

Therefore, perimeter of the semi-circular protractor is  36 cm

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#### APPEARS IN

RD Sharma Class 10 Maths
Chapter 13 Areas Related to Circles
Q 12 | Page 68