1. Warm-Up x + 2 3x - 6 What is the value of x?

2. Geometry 3-3 Proving Lines Parallel

4. Use the Converse of the Corresponding Angles Postulate and the given information to show that ℓ || m. Example: Using the Converse of the Corresponding Angles Postulate m3 = (4x – 80)°, m7 = (3x – 50)°, x = 30

5. Converse of the Alternate Interior Angle Theorem: If two alternate interior angles are congruent, then the lines are parallel. Converse of the Alternate Exterior Angle Theorem: If two alternate exterior angles are congruent, then the lines are parallel. Converse of the Same Side Interior Angle Theorem: If two same side interior angles sum up to 180°, then the lines are parallel.

6. m2 = (10x + 8)°, m3 = (25x – 3)°, x = 5 Show that r || s. Example 2: Determining Whether Lines are Parallel