Question

Find the perimeter of a semicircle having diameter 21 cm

Answer 1

Answer:

33cm

Step-by-step explanation:

Radius of the circle = 21/2

Perimeter of the circle =2pieR

=2 x 22/7 x 21/2

= 462/7

= 66cm

Perimeter of semi circle = 66/2

= 33

Answer 2

Given:

We have given the diameter of the circle is 21 cm.

To Find:

We will find the perimeter of the semicircle?

Step-by-step explanation:

• We have given in the question  the diameter of the circle which is measured as 21cm we can find the radius of circle by dividing the diameter by 2.
• The radius of the circle will be given as the

       $Radius=\frac{21}{2}$

• Now we also know the perimeter of the semicircle is equal to the circumference of the semicircle.
• Thus, the circumference of the semicircle will be given by the formula.

        $\textrm{Circumference of semicircle}=\pi r$

• Now put the value of pi and the radius in the above equation we get.

       $\textrm{Circumference of semicircle}=\frac{22}{7} \times21$

• Now simplify the above equation we get the result.

       $\textrm{Circumference of semicircle}=22\times3=66$

Hence, the circumference of the semicircle is 66cm.