Question

How to determine whether a quadrilateral is a parallelogram?

Answer 1

To prove a quadrilateral is a parallelogram, you must use one of these five ways.

Prove that both pairs of opposite sides are parallel.

Prove that both pairs of opposite sides are congruent.

Prove that one pair of opposite sides is both congruent and parallel.

Prove that the diagonals bisect each other.

Answer 2

we can determine whether a quadrilateral is parallogram if its
1 opposite sides are equal and parparal
2 sum of alternate interior angle is 180°