Center of a Circle

Pronunciation: /ˈsɛn.tər ʌv ə ˈsɜr.kəl/ Explain

All points on a circle are equidistant from the center of the circle. When we use a compass to draw a circle, the point of the compass is the center of the circle, and the stylus marks all points that are the same distance from the center.

Figure 1 - Using a compass to draw a circle.

How to Draw the Center of a Circle

Click on the blue points and drag them to change the figure. Click on the point on the slider and drag it to see each step. Manipulative 1 - How to Find the Center of a Circle Created with GeoGebra.

Draw any chord of the circle. Label the endpoints of the chord as points A and B. Draw a circle with the center at point A, and length AB. Draw a circle with the center at point B, and length AB. Draw a point at each of the intersections of the two circles. Label the points of intersection C and D. Draw a line through points C and D. Draw a point at each of the intersections of line CD and the original circle. Label the points E and F. Draw a circle with center E and length EF. Draw a circle with center F and length EF. Draw a point at the intersections of the last two circles and label the points G and H. Draw a line throught points G and H. Draw a point at the intersection of lines EF and GH. This is the center of the circle.

References

1. McAdams, David E.. All Math Words Dictionary, center of a circle. 2nd Classroom edition 20150108-4799968. pg 31. Life is a Story Problem LLC. January 8, 2015. Buy the book

More Information

• McAdams, David E.. Circle. allmathwords.org. Life is a Story Problem LLC. 6/27/2018. http://www.allmathwords.org/en/c/circle.html.
• wikiHow Staff. How to Find the Center of a Circle. www.wikihow.com. WikiHow - How to do Anything. 3/3/2019. https://www.wikihow.com/Find-the-Center-of-a-Circle.

Cite this article as:

McAdams, David E. Center of a Circle. 3/3/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/c/centercircle.html.

Image Credits

• All images and manipulatives are by David McAdams unless otherwise stated. All images by David McAdams are Copyright © Life is a Story Problem LLC and are licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.
• Using a compass to draw a circleGeoTeach.com. Used by permission.

Revision History

3/3/2019: Added how to draw the center of a circle. (McAdams, David E.)
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.)
1/9/2010: Added "References". (McAdams, David E.)
3/25/2008: Revised More Information to match current standard. (McAdams, David E.)
2/5/2008: Changed wording of definition. (McAdams, David E.)
7/30/2007: Initial version. (McAdams, David E.)