1. MS Algebra A-F-IF-7 – Ch. 6.5b Write Equations of Perpendicular Lines
Mr. Deyo
Write Equations of Perpendicular Lines

2. Title: 6.5b Write Equations of Perpendicular Lines
Date:
Learning Target
By the end of the period, I will write equations of perpendicular lines.
I will demonstrate this by completing Four-Square Notes and by solving problems in a pair/group activity.

3. Home Work 1-2-3: 1) Class 4-Square Notes Put In Binder?
2) Section 6.5 Pg ) Section ______
TxtBk.Prob.#12,22,23,24,25,26 Notes Copied on blank sheet Solved and Put in Binder? of paper in Binder?
Table of Contents
Date Description Date Due

4. Storm Check (Think, Write, Discuss, Report) Questions on which to ponder and answer:
How are the two images similar?
How are they different?
How can these two images be related to math?
IMAGE 1
IMAGE 2

5. Daily Warm-Up Exercises
For use with pages xxx–xxx
You play tennis at two clubs. The total cost C (in dollars) to play for time T (in hours) and rent equipment is given by
C = 15T + 23 at one club and C = 15T + 17 at the other. What is the difference in total cost after 4 hours of play?

6. Daily Warm-Up Exercises
For use with pages xxx–xxx
You play tennis at two clubs. The total cost C (in dollars) to play for time T (in hours) and rent equipment is given by
C = 15T + 23 at one club and C = 15T + 17 at the other. What is the difference in total cost after 4 hours of play?
ANSWER $6

7. Vocabulary Slope Parallel Lines Perpendicular Lines
Slope-Intercept Form
Point-Slope Form

8. Vocabulary Acquisition
Friendly Definition
Sketch
Wordwork
Sentence
DAY 2
1. Review word
Friendly Definition
Physical Representation
2. Draw a sketch
DAY 1
Use Visuals
Introduce the word
Friendly Definition
Physical Representation
Use Cognates
Write friendly definition
Word List
Vocabulary Acquisition
DAY 3 and/or DAY 4
1. Review the word
Friendly Definition
Physical Representation
2. Show how the word works
Synonyms/antonym
Word Problems
Related words/phrases
Example/non-example
DAY 5
1. Review the word
Friendly definition
Physical Representation
3. Write a sentence
at least 2 rich words (1 action)
correct spelling
correct punctuation
correct subject/predicate agreement
clear and clean writing

9. = m1 -1 1 m2 (m1)(m2) = -1(1) Perpendicular Lines m1 = m2 =
Notes:
Two different non-vertical lines in the same plane
are perpendicular if their slopes are negative reciprocals. m m2
Y2 – Y1
Y3 – Y4
m1 =
m2 = =
X2 – X1
X3 – X4
y – Y1 = m1(x – X1)
y = m1x + b
y – Y3 = m2(x – X3)
y = m2x + b
(m1)(m2) = -1(1)

10. Write an equation of a perpendicular line
Step 1: Identify the slope. Find the Negative Reciprocal.
Problem A
Step 2: Find the y-intercept
Step 3: Write general y = mx + b equation
Write an equation of the line that passes through (4, -5) and is perpendicular to the line y = 2x + 3

11. Write an equation of a perpendicular line
Step 1: Identify the slope. Find the Negative Reciprocal.
Problem A
Step 2: Find the y-intercept
Step 3: Write general y = mx + b equation
Write an equation of the line that passes through (4, -5) and is perpendicular to the line y = 2x + 3
SOLUTION
STEP 1
Identify the slope.
The graph of the given equation has a slope of 2. Because the slopes of perpendicular lines are negative reciprocals, the slope of the perpendicular line through (4, -5) is -1/2.
STEP 2
Find the y-intercept.
Use the slope and the given point.
Write slope-intercept form. = y + mx b = 5 + b – 2 1 ( ) 4
Substitute –(1/2) for m, 4 for x, and -5 for y. = 3 b –
Solve for b.
STEP 3
Write an equation. = y + mx b
Write slope-intercept form. = y 3 2 1 – x
Substitute –(1/2) for m and -3 for b.

12. Step 1: Identify the slope. Find the Negative Reciprocal.
Problem B
Step 2: Find the y-intercept
Step 3: Write general y = mx + b equation
Write an equation of the line that passes through the given point and is perpendicular to the given line.
(4, 3), y = 4x - 7

13. Step 1: Identify the slope. Find the Negative Reciprocal.
Problem B
Step 2: Find the y-intercept
Step 3: Write general y = mx + b equation
Write an equation of the line that passes through the given point and is perpendicular to the given line.
(4, 3), y = 4x - 7
ANSWER
y = -(1/4)x + 4

14. Storm Check (Think, Write, Discuss, Report)
How can you verify mathematically if two lines are perpendicular?
I can verify that two lines are perpendicular when
_______________________________________________
______________________________________________.

15. Vocabulary Slope Parallel Lines Perpendicular Lines
Slope-Intercept Form
Point-Slope Form

16. Title: 6.5b Write Equations of Perpendicular Lines
Date:
Learning Target
By the end of the period, I will write equations of perpendicular lines.
I will demonstrate this by completing Four-Square Notes and by solving problems in a pair/group activity.

17. Home Work 1-2-3: 1) Class 4-Square Notes Put In Binder?
2) Section 6.5 Pg ) Section ______
TxtBk.Prob.# 12,22,23,24,25,26 Notes Copied on blank sheet Solved and Put in Binder? of paper in Binder?
Table of Contents
Date Description Date Due

18. y = -2x – 5 y = -½x + 4 y = 2x – 3 y = ½x + 4
Ticket Out
Multiple Choice
Which line is perpendicular to the line y = -2x+4?
Explain your answer.
y = -2x – 5
y = -½x + 4
y = 2x – 3
y = ½x + 4
The two lines are perpendicular because ________________
__________________________________________________
_________________________________________________.

19. Their slopes are negative reciprocals.
Ticket Out
Multiple Choice
Which line is parallel to the line y = -2x + 4 ?
y = -2x – 5
y = -½x + 4
y = 2x – 3
y = ½x + 4
ANSWER C
Their slopes are negative reciprocals.