Area of a Trapezoid

Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is unnecessary since the definition of trapezoid is a four-sided figure with a pair of parallel opposite sides. Learners can then verify that the formula for the area of a trapezoid is ½(b1 + b2)h.