Answer/Step-by-step explanation:
To find the area of the parallelogram, multiply the base of the perpendicular by its height. It should be noted that the base and the height of the parallelogram are perpendicular to each other, whereas the lateral side of the parallelogram is not perpendicular to the base.
The area of this parallelogram is its height (half-height of the trapezoid) times its base (sum of the bases of the trapezoid), so its area is half-height × (base1 + base2). Because the parallelogram is made from the same “stuff” as the trapezoid, that's the area of the trapezoid, too.