## Isosceles trapezoid - Wikipedia

Rectangles and squares are usually considered to be special cases of isosceles trapezoids though some sources would exclude them. Another special case is a 3-equal side trapezoid, sometimes known as a trilateral trapezoid or a trisosceles trapezoid. They can also be seen dissected from regular polygons of 5 sides or more as a truncation of 4 sequential vertices.