Concentric circles


Concentric circles are coplanar circles that share the same center. However, radii of concentric circles are not congruent or equal.

Concentric circlesConcentric circle


The circles above are examples of concentric circles. Notice that the radius of the smaller circle is shown in black while the radius of the big circle is shown in red. 

The region outside the smaller circle but inside the big circle is called annulus. 

To name a circle, we use the name of the center. Since concentric circles have the same center, you may wonder how to name concentric circles.

You may use the radii to that end!

For example, to name the big circle, you could say circle with center A and radius Y.

Recent Articles

  1. Quadratic Formula: Easy To Follow Steps

    Jan 26, 23 11:44 AM

    Quadratic formula
    Learn about the quadratic formula, the discriminant, important definitions related to the formula, and applications.

    Read More

  2. Area Formula - List of Important Formulas

    Jan 25, 23 05:54 AM

    Frequently used area formulas
    What is the area formula for a two-dimensional figure? Here is a list of the ones that you must know!

    Read More

Tough algebra word problems

100 Tough Algebra Word Problems.

If you can solve these problems with no help, you must be a genius!

Math quizzes

 Recommended

Math vocabulary quizzes