Question

What is a parallelogram?

Answer 1

A Parallelogram is a simple quadrilateral with opposite sides parallel and equal in length

Properties of Parallelogram

Opposite sides are parallel

Opposite sides are equal in length

Opposite angles are equal (angles "a" are the same, and angles "b" are the same)

Angles "a" and "b" add up to ${180}^{\circ }$, so they are supplementary angles.

A quadrilateral is a parallelogram if:
1) Both pairs of opposite sides are parallel. (By definition).
2) Both pairs of opposite sides are congruent. If they are congruent, they must also be equal.