d=2r

These instructions are written in a simple format to explain how to find the diameter of a circle.
The diameter of a circle is 2 x the radius and is basically the span of two radii across the circle's center point thus forming a horizontal line across the entire circle like the example shows. The formula is expressed as: d=2r , where d is the diameter and r is the radius.
For example, if r=4 , then you multiply 4 by 2. In this case the diameter would be 6. d=8
You always multiply the radius x 2 to get the diameter of a circle.
You can divide the diameter by 2 to get the radius of a circle if the diameter is known.
See also: Find diameter and circumference of a circle | Formula for finding the area of a rectangle | What is a circle? | What is the radius of a circle? | What is the diameter of a circle? | What is the circumference of a circle?