The document discusses comparing slopes of parallel and perpendicular lines. It reviews that slope is rise over run and is represented by m. Parallel lines have equal slopes, while perpendicular lines have slopes that are negative reciprocals of each other. Examples are given of identifying the higher or more negative slope between two lines. Students are then given guided practice problems to write equations for parallel and perpendicular lines and identify them based on their slopes.

1. MORE ON SLOPES
Algebra 1 – Summer 2013
Mr. Saucedo

2. Objective
 We will learn to compare slopes of
parallel and perpendicular lines.

3. REVIEW: SLOPE IS…
 Rise / run
 Rate of change
 Change in y /
Change in x
 Represented by the
letter “m”
12
12
xx
yy
−
−

4. REVIEW: DESCRIBING SLOPE

5. CORRELATION

6. COMARING POSITIVE SLOPES
Which line has a higher slope?

7. COMPARING NEGATIVE SLOPES

8. Conclusion on comparing slopes

9. Guided practice:
 List in order from
lowest to highest
slope.

10. Parallel lines have equal slope.
m=3 m=-4/5

11. Perpendicular lines have negative
reciprocal slopes.
Slope of red line:
m=3x.
Slope of blue line
m=-1/3

12. Guided pracitce
1. Write an equation that is parallel to
the line: y=10x – 6
2. Write an equation that is
perpendicular to the line: y=10x - 6

13. Guided practice:
 Which equation is perpendicular to
the line y=5x -3?
a. y=5x + 2
b. Y=-5x – 3
c. Y= (1/5) x – 3
d. Y = -(1/5)x

14. Guided Practice
 Which equation is parallel to y=5x –
3
a. Y = -5x
b. Y= 5x
c. Y=(1/5)x – 3
d. Y = -(1/5)x - 3

15. INDEPENDENT PRACTICE
Using the graph:
a. Find an equation of
the line.
b. Find an equation
of a parallel line.
c. Find an equation of
a perpendicular line.
d. Graph lines b and c.

16. INDEPENDENT PRACTICE
1. Which slope is
the most positive?
2. Which slope is
the most negative?