1. Special Angles on Parallel Lines

2. Transversal A line intersecting two or more other lines in the plane.
How many angles are created by the transversal in this picture?

3. Angles that lie in the same position on opposite lines
Corresponding Angles
Angles that lie in the same position on opposite lines

4. Alternate Interior Angles
Angles that lie in between 2 lines on opposite sides of the transversal.

5. Alternate Exterior Angles
Angles that lie outside of the 2 lines on opposite sides of the transversal

6. Consecutive Interior Angles
Angles that lie in between two lines that are on the same side of the transversal

7. Let’s look deeper at those angles
Open 3.2 Angles on Parallel Lines Investigation on scevmath.org and geogebra.
Work through the investigation. Fill in the blanks, answer question 8 on your desk and be sure to answer the last question on a piece of paper to be handed in (finding the missing angle measures).

8. Conjectures
If two parallel lines are cut by a transversal, then corresponding angles are congruent.
If two parallel lines are cut by a transversal, then alternate interior angles are congruent.
If two parallel lines are cut by a transversal, then alternate exterior angles are congruent.

9. Conjectures continued…
If two parallel lines are cut by a transversal, then consecutive interior angles are supplementary.

10. Which Pair is Which?

11. 1) Name an angle that is an Alternate Interior Angle with angle g
1) Name an angle that is an Alternate Interior Angle with angle g. 2) Name a pair of angles that are supplementary and tell me WHY you know that. 3) If k = 108 degrees, find j and f 4) If d = 34 degrees, find g and f.