1. Chapter 3 Section 3-1: Properties of Parallel Lines
Goal 2.02: Apply properties, definitions, and theorems of angles and lines to solve problems and write problems and write proofs.

2. Turn in Cumulative Review Check Skills: p 115 (1-6)

3. Essential Questions
How are angles formed by 2 lines and a transversal identified?
How are the properties of parallel lines used to determine angle measure?

4. Transversal
a line that intersects two or more coplanar lines in different points

5. Alternate Interior Angles
(alt. int.  ‘s) two nonadjacent interior angles on opposite side of the transversal

6. Same-Side Interior Angles
Also called consecutive angles (s-s int.  ‘s) two interior angles on the same side of the transversal

7. Corresponding Angles
(corres.  ‘s) two angles in corresponding positions relative to the two lines

8. Examples, p 118
5) 7) Together: p (6,8)

9. Examples
2 and 3
SPQ and PSR
Together: 2, 4

10. Theorem about Parallel Planes
If two parallel planes are cut by a third plane, then the lines of intersection are parallel.

11. Example
Use # 9 for 4th property of: if 2 parallel lines are cut by a transversal then …. P

12. P 120 Two lines and a transversal form how many pairs of the following
P 120 Two lines and a transversal form how many pairs of the following? 19 Alternate interior angles 20 corresponding angles 21 same-side interior angles 22 vertical angles

13. Postulate and Theorems about angles formed by 2 Parallel lines and a transversal
If two parallel lines are cut by a transversal, then the corresponding angles are congruent. (post)
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 same-side interior angles are supplementary.
If a transversal is perpendicular to one of two parallel lines, then it is perpendicular to the other also.

14. Practice With a partner: p 119 (12- 16 even) p 120 (23-25 all)
Go over.
Individually: Practice 3-1 Worksheet

15. Summarize
List the 4 things you know if 2 parallel lines are cut by a transversal Standardized Test Prep: p. 121 (37-41 all)

16. Homework Mixed Review: p 121 (42- 50 all)
Worksheet: Definitions worksheet
Review