Library/Geometry/Plane geometry/Quadrilaterals/Parallelograms/Special cases/Parallelograms: special cases (other)

Parallelograms: special cases (other)

Overview
Important

A general parallelogram is a quadrilateral with both pairs of opposite sides parallel, but which is not a rectangle, rhombus, or square. These are sometimes called 'generic parallelograms' or 'non-special parallelograms.'

Important properties

  • Opposite sides are equal in length.

  • Opposite angles are equal.

  • The diagonals bisect each other but are not necessarily equal or perpendicular.

  • Adjacent angles are supplementary (add up to 180°).

  • Not all sides are equal, and not all angles are right angles.