Parallelogram
What is a parallelogram?
A parallelogram is a quadrilateral or a shape with 4 sides with the following properties. These properties of a parallelogram can also be viewed as parallelogram law.
Properties of a parallelogram
 opposite pairs of sides equal in length and parallel
 opposite angles equal
Thus, the following properties of a parallelogram also emerge:
 The diagonals of a parallelogram bisect each other
Example of a parallelogram
Below is an example of a parallelogram with sides a and b. The perimeter of a parallelogram is just the sum of the lengths of the sides, in this case 2xa + 2xb.
How are a parallelogram and a trapezoid alike?
Both the parallelogram and the trapezoid (trapezium) have at least one parallel sides. While the parallelogram has both the opposite sides parallel, the trapezoid or trapezium only has one.
