1. Using Properties of Parallel Lines Sec. 3.5 p. 157 GOAL: To use properties of parallel lines

2. Theorem 3.12 Theorem 3.12 – The 5 th way to prove two lines are parallel! m p In a plane, two lines perpendicular to the same line are parallel. n

3. Theorem 3.11 qpr If two lines are parallel to the same line, then they are parallel to each other.

4. Example Which lines if any must be parallel? e b c a d

5. Example Which lines if any must be parallel? c e a d b

6. Example Which lines if any must be parallel? m n dc

7. Two-Column Proof Given: Prove: Statements Reasons 1 2 B A C