# Concentric

Pronunciation: /kənˈsɛn.trɪk/ Explain

 Click on the green points and drag them to change the figure. Manipulative 1 - Concentric Circles Created with GeoGebra.

Two geometric shapes are concentric if they have the same center.[2] Concentric circles have a common center and different radii.[3] Eccentric figures (excentric in British English) do not have the same center.

 Click on the green points and drag them to change the figure. Manipulative 2 - Concentric Squares Created with GeoGebra.

### References

1. McAdams, David E.. All Math Words Dictionary, concentric. 2nd Classroom edition 20150108-4799968. pg 41. Life is a Story Problem LLC. January 8, 2015. Buy the book
2. Stöcker, K. H.. The Elements of Constructive Geometry, Inductively Presented. pp 44-45. Translated by Noetling, William A.M, C.E.. www.archive.org. Silver, Burdett & Company. 1897. Last Accessed 6/25/2018. http://www.archive.org/stream/elementsofconstr00noetrich#page/44/mode/1up/search/concentric. Buy the book
3. Phillips, Andrew W.; and Fischer, Irving. Elements of Geometry. pg 74. www.archive.org. Phillips-Loomis Mathematical Series. Harper & Brothers Publishers. 1899. Last Accessed 6/25/2018. http://www.archive.org/stream/elementsgeometr02fishgoog#page/n86/mode/1up/search/concentric. Buy the book

McAdams, David E. Concentric. 12/21/2018. All Math Words Encyclopedia. Life is a Story Problem LLC. https://www.allmathwords.org/en/c/concentric.html.

### Revision History

12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)
6/25/2018: Removed broken links, updated license, implemented new markup, updated GeoGebra apps. (McAdams, David E.)
1/18/2010: Corrected caption for manipulative 2. (McAdams, David E.)