Answer:
The answer is "lengths of opposite sides are equal "
Explanation:
The parallelogram is a four-sided one in parallel opposites and therefore opposite angles equal. Each quadrilateral is called a rhombus with equal sides, as well as a parallelogram that also has correct angles is recognized as a rectangle. Its flat form with 4 smooth edges is parallel on the other side, so that when the opposite sides were equal in length. That's why ABCD is also a parallelogram because the two sides are parallel.