Parallelograms

A parallelogram is a quadrilateral that has two pairs of parallel sides.

1. The opposite sides are equal in length.
2. The opposite angles are congruent.
3. The diagonals bisect each other.

If a quadrilateral has one of the following conditions, then it is a parallelogram.

1. If a quadrilateral has two pairs of parallel sides, then it is a parallelogram.
2. If a quadrilateral has two pairs of opposite sides of the same lengths, then it is a parallelogram. Drag point A.
3. If two pairs of opposite angles of a quadrilateral are the same, then the figure is a parallelogram.
4. If the diagonal of a quadrilateral bisect each other, the figure is a parallelogram. Drag point A and point B. Point C is point symmetry with point A about point O. Point D is point symmetry with point B about point O.
5. If a quadrilateral has one pair of opposite sides which are parallel and equal in length, then the figure is a parallelogram. AD and BC are parallel and equal in length. Drag point A and point B.