A quadrilateral with two pairs of parallel sides is called a parallelogram. A parallelogram is usually named by the name of the figure plus the four vertices in sequence.

The perimeter of a parallelogram can be calculated by multiplying (base 1 + base 2); if "a" represents base 1, "b" represents base 2, and "c" represents the perimeter of a parallelogram, then the perimeter of the parallelogram is c=2(a+b).