the isosceles trapezoid (like an isosceles triangle)... Properties of the sides of an isosceles trapezoid: trapezoid. The bases (top and bottom) of an isosceles trapezoid are parallel. Opposite sides of an isosceles trapezoid are the same length (congruent). read more
A trapezoid is a quadrilateral with exactly one pair of parallel sides (the parallel sides are called bases). The following figure shows a trapezoid to the left, and an isosceles trapezoid on the right. read more