1. Proving Lines Parallel
Section 3.2

2. Remember Postulate 3.1 told us that: If two parallel lines are crossed by a ____________________, then corresponding angles are ______________________.
Write the converse of this Postulate: ___________________________________________________________________________ We will prove this theorem true. How will it be useful? 1___________________________________________________________________________ 2. __________________________________________________________________________

3. Theorem 3.1: If Two Parallel lines are crossed by a transversal, then the alternate interior angles are congruent.
Write the converse of This theorem:_________________________________________________________________
_________________________________________________________________________
We will later prove this theorem be true. How could this be useful?
1.________________________________________________________________________
2. ________________________________________________________________________

4. WE also learned Theorem 3
WE also learned Theorem 3.2: If two parallel lines are crossed by a transversal, then the same side interior angles are supplementary.
Write the converse:_________________________________________________________________
__________________________________________________________________________
We will later prove this converse true. How can it be useful?
1. _______________________________________________________________________
2. _______________________________________________________________________

5. Example: Determine the value of x for which A ∥ B, IF M∠1 = 80 –X, AND M∠2 = 90-2X.