# Geometry/Appendix B

### Section 2.3 - Using Proofs in Geometry

1.

• Angle 2 = 120 degrees since it is supplementary to angle 1. Supplementary angles are any two angles whose sum is 180 degrees.
• Angle 3 = 60 degrees since
• Angle 1 and Angle 3 are vertical angles. Vertical angles are two nonadjacent angles formed by two intersecting lines.
• Angle 4 = 120 degrees since it is supplementary to angle 1.
• Angle 5 = angle 1 by the Transversal Postulate.
• Angle 6 = angle 2, angle 7 = angle 3, and angle 8 = angle 4 by the Transversal Postulate.

2.

• Angle 2 = angle 3 is given
• Lines R and S are parallel by the Alternate Interior Angles Converse Postulate

## Chapter 5

### Section 5.1 - Methods of Proving that Triangles are Congruent

1. Yes; triangle RUN = triangle DIH by ASA

2. No; the sides and angles do not match

3. Yes; triangle SUM = triangle HRC by ASA

4. Yes; triangle QWE = triangle TYR by SSS