Question

If the perimeter of a semicircular protractor is 54cm, find diameter and radius

Answer 1

Answer:

Perimeter of semicircle = pi*r + 2r

=) 54cm = 22/7 * r + 2r

=) 54cm = 36r/7

=) 54*7/36 cm = r

=) 10.5cm = r

So d = 2r

= 21cm.

Step-by-step explanation:

I hope this helps you.

Answer 2

Given,

The perimeter of a semicircular protractor is 54cm.

To Find,

The diameter and radius =?

Solution,

We can solve the question as follows:

It is given that the perimeter of a semicircular protractor is 54cm. We have to find the radius and the diameter.

The formula for the perimeter of a semicircle is given as:

$Perimeter\: of\: semicircle = \pi r + 2r$

Where, $r = radius$

Substituting the given value of the perimeter in the above formula.

$54 = \pi r + 2r$

Now, we will solve the above equation to find the value of the radius.

$54 = r(\pi + 2)$

Taking $\pi = \frac{22}{7}$,

$54 = r(\frac{22}{7} + 2)$

$54 = r(\frac{22 + 14}{7} )$

$54 = r(\frac{36}{7} )$

$r = 54*\frac{7}{36} = \frac{378}{36}$

$r = 10.5\: cm$

The diameter will be equal to twice the radius.

Therefore,

$Diameter= 2*r$

                $= 2*10.5$

                $=21\: cm$

Hence, the radius and the dimater are equal to 10.5 cm and 22 cm.