# Orthocenter

Pronunciation: /ˈɔrθ.oʊˌsɛn.tər/ Explain

 Click on the blue dots and drag them to change the figure. Is it possible to change the figure so that the orthocenter is outside of the triangle? Why? Manipulative 1 - Orthocenter Created with GeoGebra.

The orthocenter of a triangle is the point where the altitudes of the triangle coincide. The orthocenter may on the interior the triangle, on the boundary of the triangle or on the exterior of the triangle.

### Discovery

1. For what class of triangle is the orthocenter on the interior of the triangle?
2. For what class of triangle is the orthocenter on the boundary of the triangle?
3. For what class of triangle is the orthocenter on the exterior of the triangle?

### References

1. McAdams, David E.. All Math Words Dictionary, orthocenter. 2nd Classroom edition 20150108-4799968. pg 132. Life is a Story Problem LLC. January 8, 2015. Buy the book

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

### Revision History

12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)