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. $RS \bot AB$ and $CB \bot AC$; Given 2. Angle RSB and angle BCA are 90 degrees; perpendicular lines form right angles 3. Angle RSB is congruent to angle BCA; right angles are congruent 4. Angle B is congruent to itself; Identity property 5. Triangle BSR is congruent to triangle BCA; AA