LibGuides: Math Help: Circumference of circles

CIRCUMFERENCE OF CIRCLES

In this module, you can study how to calculate the distance around a circle (its circumference) if you know its diameter.

The circumference of a circle is not equal to the length of two diameters.

A circle's circumference divided by its diameter is the same for every circle. (It's pi, or 3.14)

Study and practice

Try your hand at changing a circumference
Drag the radius of this circle to resize it and watch what happens to the circle's circumference (called perimeter in this example). If you have trouble with this virtual manipulative, try opening it in "full screen" mode.
Study how to find the circumference of a circle
This online lesson from onlinemathlearning.com provides a good explanation about how to use either radius or diameter to calculate the circumference of a circle. It includes a couple of embedded videos.
Download a worksheet for area and circumference of a circle
Link to math-aids.com to create your own worksheets for studying area and circumference of a circle. Answers included.