Parallelogram

The parallelogram is a simple (non-self-intersecting) quadrilateral with two pairs of parallel sides. The opposite or facing sides of a parallelogram are of equal length and the opposite angles of a parallelogram are of equal measure.

Special cases of a parallelogram:


 * Rectangle – A parallelogram with four angles of equal size (right angles).
 * Rhombus – A parallelogram with four sides of equal length.
 * Square – A parallelogram with four sides of equal length and angles of equal size (right angles).