This document discusses slope and how it relates to parallel and perpendicular lines. It defines slope as the ratio of rise over run between two points on a line. Slope can be positive, negative, zero, or undefined. Parallel lines have the same slope, while perpendicular lines have slopes that multiply to -1. The document provides examples of finding slope and using properties of parallel and perpendicular slopes to determine relationships between lines. It directs students to practice problems in their groups.

1. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 1
September 27, 2013
Oct 5­4:02 PM
BELLWORK
1. Find the value of x that make p // q.
2. Which lines are parallel?
(2x + 43)
(3x)
#1
95
85
80
100
E
D
F
G
3. Can you prove a // b?
4. If so, what theorem would you use?
5. Are you ready for the 3.1­3.3 Quiz
on Monday?
p
q
a
b
#3­4
x = 43
EF // DG
yes
Alt. Interior < Converse
I hope so!

2. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 2
September 27, 2013
Oct 5­4:19 PM
3.4 Find and Use Slopes of Lines
Slope: ratio of vertical change (rise) to horizontal change (run)
between any 2 points.
Slope = rise change in y y 2 - y1
run change in x x 2 - x1
Negative Slope: falls from left to right
Positive Slope: rises from left to right
Zero Slope: horizontal line
Undefined Slope: vertical line
==
run (x2 - x1)
rise (y2 - y1)

3. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 3
September 27, 2013
Oct 5­4:31 PM
Comparing Slopes: When 2 lines intersect, the steeper line has
the slope with greater absolute value.
Postulate 17: Slopes of Parallel Lines
2 lines are // iff they have the same slope.
m1 = m2
Postulate 18: Slopes of Perpendicular Lines
2 lines are iff the product of their slopes is -1.
m1 * m2 = -1

4. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 4
September 27, 2013
Oct 6­11:50 AM
With your group, complete #3 in guided practice.

5. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 5
September 27, 2013
Oct 6­11:48 AM

6. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 6
September 27, 2013
Oct 6­11:54 AM

7. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 7
September 27, 2013
Oct 6­12:23 PM
With your group,
complete problems 4 & 5 in guided practice.

8. 3.4 Slope
HW pg. 175 #3­9 odd, 13­29 odd 8
September 27, 2013
Oct 6­1:19 PM
HW pg. 175 #3-9 odd, 13-29 odd