A parallelogram is a quadrilateral in which both pairs of opposite sides are parallel. Its properties include:
- Opposite sides are parallel.
- Opposite sides are congruent.
- Opposite angles are congruent.
- Consecutive angles are supplementary.
- Each diagonal divides the figure into 2 congruent triangles.
- Both diagonals together divide the figure into 2 pairs of congruent triangles. All 4 triangles have equal area.