Answer:
See diagram
Explanation:
A quadrilateral becomes a parallelogram when the diagonals bisects each other at a point E and hence proves the quadrilateral is a parallelogram. It shows both pairs of opposite sides being parallel to each other.
Following the theorem that states that, if two sides of a quadrilateral are opposite and congruent, then it is a parallelogram. Ditto for the theorem that states that, that when diagonals cuts each other at a point in a quadrilateral, then its a parallelogram.