What is the exact circumference of a circle?

Hey there!

When we talk about circles, geometry, shapes, or even real life, when we say circumference, we usually mean the distance around something.

Therefore, it's nothing different here. When we find the circumference of this circle, we're looking for the distance around it. The formula to do so is as follows:

C = 2πr

If we look in the answer selection, we find that we will not be approximating the irrational number of pi to 3.14, and we will just be doing our circumference in terms of pi.

Since we already know that we're going to multiply for with the 2 and the π, we need to find the radius. In our circle diagram. In this diagram, it shows us the diameter- the distance from one side to another. In order to find the distance to the midpoint from one side(the radius), we divide the diameter by 2. Therefore, our radius is 20 feet. We have:

C = 2πr
C= 2π(2)
C= 40π

Your answer is the third option.

Hope this helps!