## Elementary Geometry for College Students (6th Edition)

The proof is in the following form: Column 1 of proof; Column 2 of proof. Thus, we have: 1. Angle 2 is congruent to angle EDC; vertical angles theorem 2. Angle 1 is congruent to angle 2; given 3. Angle EDC is congruent to angle 1; transitive property 4. Angle A is congruent to itself; identity property 5. Triangles ACD and ABE are similar; AA similarity theorem 6. $\frac{AB}{AC} = \frac{BE}{CD}$; CPSSTP