We know that in a parallelogram the diagonals bisect each other.
The diagonals can't be parallel as they intersect, and they don't need to be perpendicular nor congruent, as the following example shows:
The quadrilateral ABCD is a parallelogram, and the diagonals AC and BD have different size.
Also, the diagonals are NOT perpendicular as the angle formed is not 90°:
This means that in a parallelogram, the diagonals bisect each other.
