Skip Discover Education Main Navigation

Explore the Science of Everyday Life
Click here for K-12 lesson plans, family activities, virtual labs and more!

Find Out Things About Circles

This page will show you how to calculate various things that pertain to a circle.

Notes about circles:

  • The radius R, or the distance from the center of a circle to its edge, is usually the defining property of a circle.

  • The diameter, or the distance across a circle that passes through the center of the circle is 2R (twice the radius).

  • The circumference, or distance around a circle is 2R.

  • The area enclosed by a circle is R2

  • Note that =3.1415926535...

What would you like to know?

I know that the of a circle is .

From this, show me how to calculate the of the circle.

Quick! I need help with:
Help typing in your math problems