1. Objective - To write equations of parallel and perpendicular lines.
Lesson 3.9 Parallel and Perpendicular Lines
3:9 Parallel and Perpendicular Lines
Objective - To write equations of parallel and perpendicular lines.
Graph the following on the coordinate plane. y x
Parallel lines have the same slope.
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series
Algebra 1 by James Wenk © 2003 published by TEACHINGpoint

2. Find the equation of a line in standard form that
is parallel to and passes through (1,3).
(1,3) or
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

3. Find the equation of a line in standard form that
is parallel to 3x - 5y = 10 and contains (-2,6).
(-2,6)
3x - 5y = 10
-3x x
-5y = -3x + 10 or
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

4. Find the equation of a line parallel to 2x + 3y = 5
with an x-intercept of 4.
(4,0)
2x + 3y = 5
-2x x
3y = -2x + 5
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

5. Perpendicular lines have slopes that are
Graph the following on the coordinate plane. y x
Lines appear
perpendicular
Perpendicular lines have slopes that are
opposite reciprocals
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

6. Find the following: Opposite Reciprocal Number Opposite Reciprocal 3
0.2 -8
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

7. Find the equation of a line in standard form that
is perpendicular to 4y - x = 6 and contains (2,5).
4y - x = 6
(2,5)
+x +x
4y = x + 6
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series

8. Find the equation of a line in standard form that is
perpendicular to 3x + 5y = 7 and contains (-4,-8).
(-4,-8)
3x + 5y = 7
-3x x
5y = -3x + 7 or
Algebra I by James Wenk © 2003 published by TEACHINGpoint as part of the Expert Systems for Teachers Series