1. Transversals and Angles 3-4A What is a transversal? What are four types of angles made by a transversal? What are the five steps in a deductive proof?

2. Definition A transversal is a line that intersects two coplanar lines at two different points. Exterior Interior 1 2 34 56 7 8 r s Transversal t

3. Angles formed by Transversals Alternate interior angles 1 2 3 4 56 78 interior

4. Angles formed by Transversals Alternate exterior angles 1 2 3 4 56 78 exterior

5. Angles formed by Transversals Same-side interior angles 12 3 4 56 78 interior

6. Angles formed by Transversals Corresponding angles 12 3 4 56 78

7. Try It Name: The transversal Two pairs of same side interior Two pairs of alternate exterior angles Two pairs of alternate interior angles Four pairs of corresponding angles 1234 5678 pq r

8. Five Step Deductive Proof 1.Rewrite the conjecture to be proved in if-then form. 2.Draw and label a figure to represent the given information. 3.State the statement to be proved in terms of the figure. 4.Plan the proof. Find a logical sequence of steps. 5.Demonstrate the argument by putting your plan into writing justifying every statement.

9. Do the rewrite, draw, and state steps All vertical angles are congruent. Rewrite: If two angles are vertical angles, then they are congruent. Draw: two angles are vertical angles A B C D E State: Given: Prove:

10. What is a transversal? A transversal is a line that intersects two coplanar lines at two different points. What are four types of angles made by a transversal? Alternate interior angles, alternate exterior angles, same-side interior angles and corresponding angles.

11. What are the five steps in a deductive proof? 1.Rewrite the conjecture to be proved in if- then form. 2.Draw and label a figure to represent the given information. 3.State the statement to be proved in terms of the figure. 4.Plan the proof. Find a logical sequence of steps. 5.Demonstrate the argument by putting your plan into writing justifying every statement.

12. Assignment Page 219, 1-5, 9-10, 19-23.