1. PARALLEL LINES IN A PLANE

2. ParallelandSkewLines

3. pgs 77-78 Parallel lines are coplanar lines that do not intersect. AB || GH Skew lines are non-coplanar lines which are neither parallel nor intersecting. AB and HI are skew Parallel planes are planes that do not intersect. plane ABCD || plane GHIJ Two segments and/or rays are parallel if and only if the lines containing them are also parallel. AB || GH

4. pg 78 TRANSVERSALS A line is a transversal if and only if it intersects two or more coplanar lines at different points. referred to as “cutting” the lines How many angles formed? x f g y h

5. pg 79 Exterior 1 2 f 3 4 Interior g 5 6 8 7 Exterior h Interior – region whose boundaries include the lines Exterior – region which has only one of the lines as its lone boundary Interior angles: 3, 4, 5, 6 Exterior angles: 1, 2, 7, 8

6. pg 80 1 2 3 4 5 6 7 8

7. EXAMPLE: 4 3 2 1 8 7 6 5 Give all the corresponding angles. 1 and 3 2 and 4 5 and 7 6 and 8 Give all the alternate interior angles. 2 and 7 3 and 6 3. Give all the alternate exterior angles. 1 and 8 4 and 5

8. 4 5 9 6 3 2 7 8 Use the figure above and identify the following pairs (next slide) whether they are one of the following: Corresponding angles Alternate interior angles Alternate exterior angles Vertical angles Linear pair

11. C and DD 2 C 1

12. Corresponding angles Alternate interior angles Alternate exterior angles Vertical angles Linear pair 4 5 9 6 3 2 7 8 9 and 3 - Alternate exterior angles 5 and 7 - Alternate interior angles 7 and 9 - Vertical angles 6 and 2 - Alternate interior angles 4 and 6 - Corresponding angles 2 and 8 - Corresponding angles 5 and 4 - Linear Pair