1. Parallel and Perpendicular Lines http://apod.nasa.gov/apod/The Dark Doodad Nebula

2. Parallel Lines Parallel Lines - lines that never intersect What is the slope of the red line? 1/2 What is the slope of the blue line? 1/2 Parallel Lines have the slope! same

3. Parallel Lines Determine if the lines are parallel 1. 2x + 6y = 12 6y = -2x + 12 yes

4. Parallel Lines Determine if the lines are parallel 2. 6x + 8y = -24 8y = -6x – 24 No

5. Equations of Parallel Lines 4. Write an equation for the line that contains (5, 1) and is parallel to m =

6. Equations of Parallel Lines 5. Write an equation for the line that contains (2, -6) and is parallel to m = 3 y + 6 = 3(x – 2)

7. Perpendicular Lines Perpendicular Lines – lines that intersect to form right angles What is the slope of the red line? -1/4 What is the slope of the blue line? 4/1 Perpendicular Lines have slope! negative reciprocal

8. Perpendicular Lines What is the slope of the perpendicular line? 7. -5/2 8. 5/1 = 5 9. 1/2

9. Equations of Perpendicular Lines 10. Find the equation of the line that contains (0, -2) and is perpendicular to y = 5x + 3 m =

10. Equations of Perpendicular Lines 11. Find the equation of the line that contains (1, 8) and is perpendicular to m =

11. Perpendicular Lines 13. Determine if the lines are perpendicular: and No 14