If b_{1}
and b_{2} are the lengths of the two parallel bases of a
trapezoid, and h is its height, the area of the trapezoid is height is perpendicular to both bases To picture this, consider two identical trapezoids, and "turn" one around and "paste" it to the other along one side as pictured below:
The figure formed is a parallelogram having an area of h · (a + b), which is twice the area of one of the trapezoids. Example: What is the area
of a trapezoid having bases 12 and 8 and a height of 5?
