# Review 2.2, 2.5, 3.5, 4.1, 5.7 #21

### A. Moore in Mr. Kirkland's Math II Class

A surveyor needs to measure the distance ,AB, across a lake. Beginning at E, he finds the midpoint ,C, of segment AE and the midpoint,D, of segment BE. He then measures segment CD. Whats is AB?