A parallelogram is a 4-sided shape formed by two pairs of parallel lines.
Opposite sides are equal in length and opposite angles are equal in measure. To find the area
of a parallelogram, multiply the base by the height.
The formula is A = Area of a parallelogram = base x height = b x h
where b is the base, h is the height, and · means multiply. 
The base and height of a parallelogram must be perpendicular.
However, the lateral sides of a parallelogram are not perpendicular to the base.
Thus, a dotted line is drawn to represent the height.
