Question

How do you find the perimeter of a semicircle that has a radius of 4 ft?

Answer 1

Hint: In order to solve this question, you need to know the formula for the perimeter of a circle. The perimeter of a circle is given by $ 2\pi r$. But since the semicircle is half the circle, we get the perimeter of a semicircle as $ \pi r$. But for a semicircle, you have an additional line of length 2r at the bottom of a semicircle. Therefore, the perimeter of a semicircle is $ \pi r+2r$. Here, substitute r = 4 ft to get the final answer.

Complete step by step solution:
The first step to solve this question is to find the perimeter of a semicircle from the perimeter of a circle. The perimeter of a circle is given by $ 2\pi r$. Semicircle is half the circle but also you have additional $2r$ diameter, therefore we get
$ \pi r+2r$.
Now, we just have to substitute the $r = 4 ft$ to get the required perimeter of the semicircle. Here, we take the perimeter P. Therefore, we get the answer as,
$ \Rightarrow P=\pi r+2r$
$ \Rightarrow P=4\pi +8$
$ \Rightarrow P=20.566ft$
Therefore, we get the final answer for the question: how do you find the perimeter of a semicircle that has a radius of 4 ft, as 20.566 ft.

Note: For solving this question, you need to know the perimeter for the circle. It is best if you directly learn the formula for the perimeter of a semicircle, so that you can solve questions like these easily.