How to Find the Circumference of a Circle?
13 Examples!

Finding the circumference of a circle is quick and easy.

Follow these easy to follow examples, and you’ll be all set.

Let’s jump in!

The circumference is the distance around a circle.

In other words, it’s the perimeter of the circle. And we find the circumference by using the formula C = 2πr.

But what do we do if we only want to find a fraction or a part of the distance around the circle?

We need the Arc Length Formula!

This means that the length on any arc can be found from its degree measure if the radius of the circle is known.

And as Math Open Reference states, the formula takes the circumference of the entire circle (2πr). It reduces it by the ratio of the degree measure of the arc angle (n) to the degree measure of the entire circle (360).

In the video below, you’ll learn how to:

1. Find the circumference.
2. Determine the arc length.
3. Calculate angle measures using both the circumference formula and the arc length theorem.

Video – Lesson & Examples

45 min

• Introduction
• 00:00:15 – Understanding circumference and the arc length theorem
• 00:06:06 – Find the circumference (Examples #1-4)
• Exclusive Content for Member’s Only

• 00:15:00 – Find the arc length, central angle, or radius (Examples #5-8)
• 00:25:07 – Find the indicated measures (Examples #9-11)
• 00:34:37 – Using the arc length theorem find the values of each variable (Examples #12-13)
• Practice Problems with Step-by-Step Solutions
• Chapter Tests with Video Solutions