2. 1. Differentiate intersecting, parallel, and skew lines; 2. Classify pairs of angles generated whenever two lines are cut by a transversal; and 3. Cite examples of parallel lines in real life.

3. Are the horizontal lines parallel?

4. are planes that do not intersect M N

5. p q are coplanar and do not intersect R

6. are not coplanar and do not intersect M N a b

7. Theorem: If two parallel planes are cut by a third plane, the lines of intersection are parallel. A B C P S R D

8. a line that intersects two coplanar lines in two different points a b c 1 2 3 4 56 78

9. Corresponding angles are two nonadjacent angles on the same side of the transversal such that one is an exterior angle and the other is an interior angle. a b c 1 2 3 4 56 78

10. Interior angles: Exterior angles: 3, 4, 5, and 6 1, 2, 7, and 8 a b c 1 2 3 4 56 78

11. Alternate interior angles are two nonadjacent interior angles on opposite sides of the transversal.  3 &  5,  4 &  6 a b c 1 2 3 4 56 78

12. Alternate exterior angles are two nonadjacent exterior angles on opposite sides of the transversal.  1 &  7,  2 &  8 a b c 1 2 3 4 56 78

13. Same-side interior angles are two interior angles on the same side of the transversal. a b c 1 2 3 4 56 78  3 &  6,  4 &  5

14. Same-side Exterior angles are two exterior angles on the same side of the transversal. a b c 1 2 3 4 56 78  1 &  8,  2 &  7

15. 12 34 5678 9 10 11 12 13 14 1516 Identify each angle pair as alternate interior, alternate exterior, same-side interior, same-side exterior, corresponding, or none of these. Try these

16. 12 34 5678 9 10 11 12 13 14 1516 1.  5 and  10 2.  6 and  7 3.  2 and  9

17. 12 34 5678 9 10 11 12 13 14 1516 4.  9 and  11 5.  5 and  8 6.  1 and  14