1. 5.8 Slope of Parallel and Perpendicular Lines

2. Language Goal Students will be able to Identify and graph parallel and perpendicular lines. Math Goal Students will be able to write equations to describe lines parallel or perpendicular to a given line. Essential Question How can you find a parallel line or perpendicular line? LEARNING TARGETS

3. WARM-UP

4. HOMEWORK CHECK

7. DISCOVERY Draw an xy-axis on your graph paper. Plot the point (0, 0) What do you notice about the two lines? What do we call these lines?

8. GRAPH

9. DISCOVERY Draw an xy-axis on your graph paper. Plot the point (0, 0) Create one line by having a slope of 2. What kind of angle do the two lines form? What do we call these lines?

10. GRAPH

11. Parallel Perpendicular VOCABULARY Lines that have no points in common. They never intersect. Lines that intersect to form right angles, 90°

12. OVERVIEW

14. EXAMPLE 1: IDENTIFYING PARALLEL LINES

18. Identify which lines are perpendicular. A. x = -2; y = 1; y = -4x; y + 2 = (x + 1) EXAMPLE 3: IDENTIFYING PERPENDICULAR LINES

19. Identify which lines are perpendicular. B. y = -4; y – 6 = 5(x + 4); x = 3; y = x + 2 EXAMPLE 3: IDENTIFYING PERPENDICULAR LINES

21. A. Write an equation in slope-intercept form for the lie that passes through (4, 5), and is parallel to the line described by y = 5x + 10. EXAMPLE 5:WRITING EQUATIONS OF PARALLEL AND PERPENDICULAR LINES

22. B. Write an equation in slope-intercept form for the line that passes through (3, 2), and is perpendicular to the line described by y = 3x – 1. EXAMPLE 5:WRITING EQUATIONS OF PARALLEL AND PERPENDICULAR LINES

24. D. Write an equation in slope-intercept form for the lien that passes through (-5, 3) and is perpendicular to the lien described by y = 5x. EXAMPLE 5:WRITING EQUATIONS OF PARALLEL AND PERPENDICULAR LINES

25. E. Write an equation in slope-intercept form for the line that passes through (4, 10) and is parallel to the line described by y = 3x + 8. EXAMPLE 5:WRITING EQUATIONS OF PARALLEL AND PERPENDICULAR LINES

26. F. Write an equation in slope-intercept form for the line that passes through (2, -2) and is perpendicular to the lien described by y = 2x – 5. EXAMPLE 5:WRITING EQUATIONS OF PARALLEL AND PERPENDICULAR LINES

27. LESSON QUIZ