© 2025 Shmoop University, Inc. All rights reserved.
 

Math Shack

< Pick a Different Problem
I'm Feeling Lucky
View Your Progress
0

Concentric Circles: Find the Radius Given the Circumference

Geometry

Answer questions correctly to move the progress bar forward. Once the progress bar is complete, you've mastered the topic.
Your browser does not support HTML5 Canvas. To get the most out of Math Shack you will need to upgrade to a more modern browser.
Loading... (If a question never loads, select another topic here)
Submit

Calculator

You Will Earn

20

Shmoints When You Master This Topic!

You've already mastered this topic. You can't earn more Shmoints for the same topic, but feel free to keep practicing.

Got Math Shack feedback? Share it with us!

Hey Teachers!

Robeefalo says...

Make homework fun.

Send a link to Math Shack. Your students will thank you.

Give Extra Credit.

For earning 100 Shmoints. The sky’s the limit.

Get Support.

If your school is using Common Core, we are all set up to support you. Click here to learn more.