Let’s draw a perpendicular line from vertex C to base AB, and label the intersection of this line segment and the bottom base E (see Figure G.54). We have divided trapezoid ABCD into rectangle AECD and right triangle BEC. First we focus on rectangle AECD. We can see EC 9, since it is the same length as the side of the rectangle opposite EC; AE 14, since it is the same length as the side of the rectangle opposite AE. Since AB 26, that leaves EB 12. Now we focus on the right triangle EBC. This
triangle has legs 9 and 12. We can use the Pythagorean theorem to find the length of the missing side, which in this case, is the hypotenuse of the right triangle.