Circumference of a Circle (Jump to: Lecture | Video )

Figure 1.

Above, we have a circle.

Figure 2.

The distance from one side of the circle to the center is called the radius.

Figure 3.

The distance from one side of the circle to another, while going through the center, is called the diameter.

Figure 4.

The distance all the way around a circle is called the circumference.

Figure 5.

Here we have a circle with a radius of 4. We can use that information to find the circle's area:

Circumference of a Circle

So, for our circle:

Circumference = 2(3.14)(4)

Circumference = 25.12