A
parallelogram is a quadrilateral with two pairs of parallel sides. Opposite sides are equal in lengh and opposite angles are equal in measure.
The sum of the measures of the angles of a parallelogram is 360.
(Squares, rectangles and rhombus are particular types of parallelograms).
Area of a paralellogram

A=b·h where b is the base and h is the height. 
Find the area:

A=b·h
A=8·6=48 units^{2}

What is the area when b=5, and h=8?