A surveyor needs to find the distance from point a to point b across a canyon. She places a stake at a and her coworker places a stake at b on the other side of the canyon. The surveyor then locates c on the same side of the canyon as a CA AB. A fourth stake is places at E, the midpoint of CA. Finally, a stake is placed at D such that CD CA and D, E, and B are sited as lying along the same line. Explain how the surveyor can use the triangles formed to find AB. If AC=1300 meters, DC =550 meters, and DE=851.5 meters, what is AB? Explain your reasoning.