A transversal is a line that intersects two coplanar lines at two distinct points. The diagram shows the eight angles formed by a transversal t and two lines l and m.

RECALL

Pairs of the eight angles have special names as suggested by their positions.

RECALL

Angles 1 and 5 are examples of

corresponding angles.

Angles 1 and 8 are examples of alternate

exterior angles.

Angles 3 and 6 are examples of alternate

interior angles.

Angles 3 and 5 are examples of same-side

interior angles.

3-1 Properties of Parallel LinesGoal 1: To identify angles formed by two lines and a transversal

Goal 2: To prove and use properties of parallel lines

Please do not proceed until told to do so!

We’re now going to explore the relationships among these special angle pairs when the two lines being intersected by a transversal happen to be parallel to one another.Activity1. Open GSP 4.06 from the start menu.2. Follow along as we complete the

Properties of Parallel Lines GSP activity steps 1-4 as a class.

3. With a partner read and complete, up to, but not including step 7. Answer all questions on the sheet.

Complete the following statements based upon your observations from the lesson:

If two parallel lines are cut by a transversal, then 1. corresponding angles are _____________________.2. alternate interior angles are _____________________.3. same-side interior angles are _____________________.4. alternate exterior angles are _____________________.

Theorems

Classwork: Practice Worksheet 3-1

Assignment: p. 118 #1-26