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

### B. Kennedy in Mr. Kirkland's Math II Honors Class

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

The diagram for the problem:

Brace map for the problem:

Therefore, the distance across the lake is 136 m.