# What is the formula for the circumference C of a circle of radius r?

**Solution:**

The circumference of a circle is the length of the boundary of the circle.

The circumference of a circle is given by multiplying 2π with its radius.

So, the formula to find the circumference of a circle C is C = 2 π r, where r is the radius.

Let us find the circumference of a circle with a radius of 7 units.

C = 2 π r

= 2 π × 7 units

= 14 π units

You can use the Circumference of Circle Calculator to find the circumference of a circle.

Therefore, the formula to find the circumference C of a circle of radius r is C = 2 π r.

## What is the formula for the circumference C of a circle of radius r?

**Summary:**

The formula to find the circumference C of a circle of radius r is C = 2 π r.

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