1. 3.3, 3.6 & 3.7 Parallel and Perpendicular lines
7.0 Students prove and use theorems involving the properties of parallel lines cut by a transversal

2. What are the characteristics of parallel lines and perpendicular lines?
Slopes are the same
Different y-intercept
Perpendicular Lines:
Slopes are opposite-reciprocal
Y-intercept doesn’t matter

3. Parallel Theorem 1
If two lines are parallel to the same line, then they are parallel to each other
Ex:
If a//b and b//c, then a//c

4. Parallel Theorem 2
In a plane, if two lines are perpendicular to the same line, then they are parallel to each other
Ex: Shown on interwrite

5. Parallel Theorem 3
In a plane, if a line is perpendicular to one of two parallel lines, then it is also perpendicular to the other
Ex: Shown on interwrite

6. Practice
What is the relationship between line a and line d?

7. Short Assignment
Pg 144 #14-21

8. Reviewing Graphing Parallel and Perpendicular lines
Slope-intercept form
Standard form
Point-slope form

9. Slope-intercept form
M= slope
B= y-intercept

10. Graphing using slope-intercept form

13. Standard Form Uses x and y intercept to find 2 points X-intercept
When y=0
(# , 0)
Y-intercept
When x=0
(0 , #)

16. Point-Slope form

17. Finding Equation using 2 points
(0,5) (5,8)

18. (8,10) (-4,2)

19. (2,-6) slope -9

20. Assignment
Pg 169 #2, 4, 6, 8, 18, 20, 24, 26

21. Are these lines parallel, perpendicular or intersecting?
Y=2x-5
Y=2x

22. Are these lines parallel, perpendicular or intersecting?

23. Are these lines parallel, perpendicular or intersecting?
3x+4y=12
6x+8y=24

24. Are these lines parallel, perpendicular or intersecting?
Y-7x=6
Y+7x=8

25. Are these lines parallel, perpendicular or intersecting?
(0,-2)(4,-4) and (4,1)(1,-5)

26. Are these lines parallel, perpendicular or intersecting?
(0,3)(4,1) and (-6,1)(0,-2)

27. Assignment
Pg 177 #4, 8, 10, 12, 16, 20