[Math Lair] Quadrilaterals

Math Lair Home > Topics > Quadrilaterals

A quadrilateral is a four-sided figure. Several types of quadrilaterals have special names:
squareA square is a quadrilateral with four equal sides and four equal (right) angles.
rectangleA rectangle is a quadrilateral with four equal (right) angles.
rhombusA rhombus is a quadrilateral with four equal sides.
parallelogramA parallelogram is a quadrilateral with two pairs of parallel sides.
trapezoidA trapezoid or a trapezium is a quadrilateral with one pair of parallel sides.
quadrilateralThere are other quadrilaterals for which none of the above definitions apply.

It can be seen from the definitions that all squares are rectangles and rhombuses, and all rhombuses and rectangles are parallelograms. The reverse is not necessarily true, however.