Incenter

Pronunciation: /ˈɪnˌsɛn.tər/ Explain

Click on the blue points to change the figure. Click on the check boxes to see the incircle and to see how to incenter is drawn. Manipulative 1 - Incenter of a Regular Polygon Created with GeoGebra.	The incenter of a polygon is a point that is the center of the circle that intersects each side of the polygon exactly once. The incircle of a triangle can be constructed by finding the intersection of the angle bisectors. The incircle of a regular polygon is located at the intersection of the perpendicular bisectors of the sides of the polygon. The incircle of a geometric figure is the circle that is tangent to all the sides of a triangle. The incircle touches each of the sides exactly once.
How to Construct the Incenter and Incircle of a Triangle 1 Pick any one angle of a triangle and construct its bisector. 2 Pick one of the remaining angles of a triangle and construct its bisector. 3 Mark the intersection of the two lines as the incenter. 4 Construct a line perpendicular to any side through the incenter. Mark the point where the line intersects the side to which it is perpendicular as point A. 5 Construct circle with the center at the incenter and the radius the distance from the incenter to point A.
How to Construct the Incenter and Incircle of a Regular Polygon Step Illustration Discussion and Justification 1 The center of a regular polygon is at the point of concurrency of perpendicular bisectors of any two sides that are not opposite each other. 2 Draw the perpendicular bisector of any side. 3 Draw the perpendicular bisector of any other side that is not opposite the side you used in step 2. 4 Label the intersection of the two perpendicular bisectors as 'center'. 5 Draw a circle with the center at the point labeled 'center' and the edge where one of the perpendicular bisectors intersects a side. Table 3 - How to construct the center and incircle of a regular polygon

References

1. McAdams, David E.. All Math Words Dictionary, incenter. 2nd Classroom edition 20150108-4799968. pg 95. Life is a Story Problem LLC. January 8, 2015. Buy the book

More Information

• McAdams, David E.. Center. allmathwords.org. Life is a Story Problem LLC. 3/12/2009. http://www.allmathwords.org/en/c/center.html.

Cite this article as:

McAdams, David E. Incenter. 4/23/2019. All Math Words Encyclopedia. Life is a Story Problem LLC. http://www.allmathwords.org/en/i/incenter.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.

Revision History

4/23/2019: Updated equations and expressions to new format. (McAdams, David E.)
12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)
8/6/2018: Removed broken links, updated license, implemented new markup, implemented new Geogebra protocol. (McAdams, David E.)
10/23/2010: Changed article to apply to incenters of a polygon, rather than just a triangle. Added section on constructing the incenter of a regular polygon. (McAdams, David E.)
2/11/2010: Added "References". (McAdams, David E.)
11/18/2008: Changed manipulative to GeoGebra. (McAdams, David E.)
8/24/2007: Simplified figure 1, added reference to triangle article, added incircle. (McAdams, David E.)
7/30/2007: Initial version. (McAdams, David E.)