Six important properties
of parallelograms to know:
Opposite sides are congruent (ON=LM)
Opposite angels are congruent (L= N)
Consecutive angles are supplementary (O+ L= 180°).
If one angle is right, then all angles are right.
The diagonals of a parallelogram bisect each other.
Each diagonal of a parallelogram separates it into two congruent triangles.