Question

If the perimeter of a semi-circular protactor is 72, find it's diameter.

Answer 1

The answer is 28 please mark brainliest if it helped you

Answer 2

We know, 
Perimeter of a circle = $2 \pi r$
Also if the figure is semicircle, it will have its diameter included in its perimeter and half of the curved edge will not be present. Therefore ,
Perimeter of a semicircle = $\pi r + 2r$

Now,
72 =$\pi r + 2r$
⇒72 = 3.14(r) +2 r
⇒72 = r(3.14 +2)
⇒72 = r(5.14)
⇒ r  = 72/5.14
⇒ r  = 14        (approx)

Hence,
   d = 2r
⇒d=2(14.00)
⇒d=28cm