Definition:Quadrilateral/Parallelogram

Definition
A parallelogram is a quadrilateral whose opposite sides are parallel to each other, and whose sides may or may not all be the same length.


 * Parallelogram.png

Also see

 * Opposite Sides and Angles of Parallelogram are Equal.


 * Rectangle is Parallelogram: a rectangle is a parallelogram all of whose angles are equal to a right angle.


 * Altitude of Rectangle: the altitude of a rectangle is equal to one of its sides which is adjacent to its base.