# Equilateral

Pronunciation: /ˌi.kwəˈlæ.tər.əl/ Explain

A polygon whose sides are the same length is called equilateral. The most commonly used equilateral polygon is the equilateral triangle. An equilateral quadrilateral is a parallelogram with equal sides. If the adjacent sides of an equilateral quadrilateral are perpendicular, the shape is a square. All regular polygons are equilateral.

The word equilateral is derived from Latin. Equi- is taken from the word aequus, meaning 'equal'. -lateral is taken from the word lateralis, meaning 'of the side'.

### Examples

 Click on the blue points and drag them to change the figure. The sides on these figures are always the same size, are always equilateral. Manipulative 1 - Equilateral Created with GeoGebra.
1. McAdams, David E.. All Math Words Dictionary, equilateral. 2nd Classroom edition 20150108-4799968. pg 71. Life is a Story Problem LLC. January 8, 2015. Buy the book
2. Carol Vorderman. Math Dictionary. pg 38. DK CHILDREN. July 20, 2009. Last Accessed 7/9/2018. Buy the book

• McAdams, David E.. Equilateral Triangle. allmathwords.org. All Math Words Encyclopedia. Life is a Story Problem LLC. 3/12/2009. https://www.allmathwords.org/en/e/equilateraltriangle.html.

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

### Revision History

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