The Lesson

The diameter of a circle is twice the radius.diameter_from_radius

How to Find the Diameter from the Radius

Finding the diameter from the radius is easy.

Question

What is the radius of the circle, with radius 5 cm, below?
diameter from radius example

Step-by-Step:

1

Multiply the radius, 5cm, by 2.
5 × 2 = 10 cm

Answer:

The diameter of the circle is 10 cm.

Lesson Slides

The slider below shows another real example of how to find the diameter of a circle from the radius.

Interactive Widget

Here is an interactive widget to help you learn about finding the diameter of a circle from its radius.

What Is a Circle?

A circle is a shape containing a set of points that are all the same distance from the center. This distance is the radius. circle_center_and_radius The diameter is the line through the center of the circle that has its endpoints on the circle. diameter_mini