1. Parallel Lines and Transversals
Chapter 3 Section 3.3
Parallel Lines and Transversals

2. Warm-Up What can you conclude about the angles?
Which is not true if m<2=90?
The lines are perpendicular.
<1 is a right angle.
The unlabeled angles are congruent.
<1 and <2 are complementary . 1 2

3. When two parallel lines are cut by a transversal, then …
Corresponding angles are 
Corresponding Angle Postulate
Alternate Interior angles are 
Alternate Interior Angle Theorem.
Alternate Exterior angles are 
Alternate Exterior Angle Theorem
Consecutive Interior angles are Supplementary
Consecutive Interior Angle Theorem

4. Perpendicular Transversal Thm.
If a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other.

5. Find the measure of 1 and 2 Explain your reasoning

6. Find the measure of 1 and 2 Explain your reasoning

7. Find the value of x and y and state the reason

8. Find the value of x and y and state the reason

9. Find the value of x and state the reason

10. Find the value of x and state the reason

11. Complete the flow proof of the Proof of the Alt. Ext. Angle Thm.