<Li> The angle between a side and a diagonal is equal to the angle between the opposite side and the same diagonal . </Li> <Li> The diagonals cut each other in mutually the same ratio (this ratio is the same as that between the lengths of the parallel sides). </Li> <Li> The diagonals cut the quadrilateral into four triangles of which one opposite pair are similar . </Li> <Li> The diagonals cut the quadrilateral into four triangles of which one opposite pair have equal areas . </Li>

A trapezoid with at least one right angle