I can't follow your reasoning at at. "Drop the height h" is completely ambiguous.
And the nice thing about Garfield's proof is that all it requires that you know is the area of a right triangle and the basic Euclidean premises. You can easily get the area of a trapezoid from that.
And the nice thing about Garfield's proof is that all it requires that you know is the area of a right triangle and the basic Euclidean premises. You can easily get the area of a trapezoid from that.