Geometry

The answer is B. 16.

 

1. Analyze the congruence of line - segments from the diagram:

In the geometric diagram, line - segments with the same number of tick marks are congruent. We can see that and both have two tick marks, which means .

 

2. Use the property of congruent line - segments:

The property of congruent line - segments states that if two line - segments are congruent, then their lengths are equal. That is, if , then .

We are given that