In geometry, a trapezoid in North American English, or trapezium (/trəˈpiːziəm/) in British English, is a quadrilateral that … See more

The ancient Greek mathematician Euclid defined five types of quadrilateral, of which four had two sets of parallel sides (known in English as square, rectangle, rhombus and rhomboid) and the last did not have two sets of par… See more

There is some disagreement whether parallelograms, which have two pairs of parallel sides, should be regarded as trapezoids.
Some define a trapezoid as a quadrilateral having onl… See more