Pronunciation: /ˈtræ pəˌzɔɪd/ ?

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Manipulative 1: Trapezoid or Trapezium. Created with GeoGebra.

A trapezoid (in American English) or trapezium (in British English) is a four sided quadrilateral where one pair of opposite sides are parallel.[1][2] The parallel sides are called bases. The other two sides are called legs. The word 'trapezoid' is used in U.S. English. The word 'trapezium' is used in U.K. English. The two words mean the same thing.


  1. Hilbert, David. The Foundations of Geometry, pg 28. Townsend, E. J., Ph. D.. The Open Court Publishing Company, 1950. (Accessed: 2009-12-21).
  2. Stöcker, K.H.. The Elements of Constructive Geometry, Inductively Presented, pp 23, 36-38. Translated by Noetling, William A.M, C.E.. Silver, Burdett & Company, 1897. (Accessed: 2009-12-28).
  3. Keller, Samuel Smith. Mathematics for Engineering Students, Plane and Solid Geometry, pg 45. D. Van Nostrand Company, 1908. (Accessed: 2010-01-02).
  4. trapezoid. WordNet. Princeton University. (Accessed: 2011-01-08).
  5. trapezium. WordNet. Princeton University. (Accessed: 2011-01-08).

Cite this article as:

Trapezoid. 2009-12-31. All Math Words Encyclopedia. Life is a Story Problem LLC.


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Revision History

2009-12-31: Added "References" (McAdams, David.)
2009-09-17: Initial version (McAdams, David.)

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