Stylish Geometry

I went to the Gilroy Outlets last weekend and visited the Coach store.  I was looking at the purses when I realized that some of the purses were perfect isosceles trapezoids.  I used Geometer's Sketchpad to prove Theorem 5-18 and Theorem 5-19.

Theorem 5-18 states that the base angles of an isosceles trapezoid are congruent and my picture shows that the base angles are both 69.89 degrees. In Theorem 5-19, the median of a trapezoid is parallel to the bases and has a length equal to the average of the base lengths.  Since segment AD and segment BC were already parallel, then segment EF was parallel as well.  I then measured and added segments AD and BC and concluded that the average was 8.71, which is the same as EF.  Therefore, I  proved that this Coach purse is an isosceles trapezoid and a fashionable accessory!  (~MG1)