Elementary Geometry for College Students (7th Edition)

The proof is in the following form: Column 1 of proof; Column 2 of proof. Thus, we have: 1. Triangles DEF and MNP are similar, and DG and MQ are the altitudes; Given 2. Angle E is congruent to angle N; CASTC 3. Angle EGD and angle NQM are 90 degrees; perpendicular lines form right angles 4. Angle EGD is congruent to angle NQM; right angles are congruent 5. Triangle EDG is congruent to triangle NMQ; AA 6. $\frac{DG}{MQ} = \frac{DE}{MN}$; CSSTP