Pronunciation: /ˈvɜr.tɛks/ Explain

A vertex is a point that is the endpoint of two or more non-collinear line segments or rays.[2][3] The plural of vertex is vertices.

Examples of Vertices
Vertex of an angle.
Figure 1: Vertex of an angle.

The vertex of an angle is the point where the lines intersect that form the angle.

Vertices of a triangle.
Figure 2: Vertices of a triangle.

The vertices of a triangle are the points where the sides of the triangle intersect.

Vertices of a polygon.
Figure 3: Vertices of a polygon.

The vertices of a polygon are the points where the sides of the polygon intersect.

Vertices of parabolas.
Figure 4: Vertices of parabolas.

A vertex is also the inflection point of a parabola or a polynomial. This is the point where the curve changes direction.


  1. McAdams, David E.. All Math Words Dictionary, vertex. 2nd Classroom edition 20150108-4799968. pg 189. Life is a Story Problem LLC. January 8, 2015. Buy the book
  2. Keller, Samuel Smith. Mathematics for Engineering Students, Plane and Solid Geometry. D. Van Nostrand Company. 1908. Last Accessed 1/2/2010. Buy the book
  3. Casey, John, LL.D., F.R.S.. The First Six Books of the Elements of Euclid. pg 7. Translated by Casey, John, LL.D. F.R.S.. Hodges, Figgis & Co.. 1890. Last Accessed 1/2/2010. Buy the book

Cite this article as:

McAdams, David E. Vertex. 12/21/2018. All Math Words Encyclopedia. Life is a Story Problem LLC.

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Revision History

12/21/2018: Reviewed and corrected IPA pronunication. (McAdams, David E.)
12/17/2018: Removed broken links, updated license, implemented new markup. (McAdams, David E.)
8/7/2018: Changed vocabulary links to WORDLINK format. (McAdams, David E.)
1/7/2010: Added "References". (McAdams, David E.)
10/11/2008: Added vertex of a polynomial. (McAdams, David E.)
6/7/2008: Corrected spelling. (McAdams, David E.)
4/23/2008: Initial version. (McAdams, David E.)

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