Question

the perimeter of a semicircle is 108 then find the diameter of the protractor

Answer 1

Answer:

42

Step-by-step explanation:

Given perimeter = 108

Perimeter of a semicircle = πr + 2r

=> Perimeter of semicircle = r(π + 2)

Hence, r(π + 2) = 108

Taking π as 22/7, we get

r(22/7 + 2) = 108

=>r(22/7 + 14/7) = 108

=> r(36/7) = 108

=> r = 108 × 7/36

=> r = 21

We know that diameter = 2r

Hence Diameter = 2 × 21

Diameter = 42

Answer 2

Protactor shape = Semicircle

Now,

Perimeter of semicircle = 108 unit (Given)

Also,

$<u>Perimeter of semicircle = Circumference of semicircle + Diameter</u>$

Circumference of semicircle = πr

Diameter = 2r

Here, r = radius

So,

πr + 2r = 108

r ( π + 2 ) = 108

r ( 3.14 + 2 ) = 108

r ( 5.14 ) = 108

r = 108 / 5.14

r = 21.01 unit

r = 21 unit ( Approx )

Diameter = 2r = 2 ( 21 )

$<b>Diameter of semicircle or protactor = 42 unit</b>$