1. Sec. 3-3 Parallel and Perpendicular Lines
Objective:
To relate Parallel & Perpendicular Lines.

2. Th(3-9) If two lines are // to the same line, then they are // to each other.1 2 k 3 4 5 6 m 7 8 9 10 n 11 12

3. Th(3-9) If two lines are // to the same line, then they are // to each other.k 5 6 m 7 8 9 10 n 11 12

4. Th(3-10) In a plane, if 2 lines are perpendicular to the same line, then they are // to each other.

5. Th(3-11) In a plane, if a line is perpendicular to one of two parallel lines, then it is parallel to the other. t r s

6. Corresponding Angles are  They are = 90 Alt. Int. s are 
Same-sided int. s are Supplementary
They are both = 90 t r s

7. Example 1: Solve for x and then solve for each angle such that n // m.
14 + 3(40) =
134 n
14 + 3x
5x - 66 m
14 + 3x = 5x -66
-3x x
14 = 2x – 66
80 = 2x 2
40 = x
5x – 66
5(40) – 66
134

8. Example 2: Find the m1 7x – 8 7(18) – 8 118 7x – 8 + 62 = 180