1. Slope
Lesson 4.6

2. Change of y over the change of x Use m for slope Equation:1 2
m = 2 1

3. m =
∆y ∆x
∆ Delta y over delta x
∆ delta means change
Rise over run

4. Find the slope of a line given two points:
(5, -2) (6, 3) 1 2
m = 2 1
3 - -2
6 - 5 5 1 =
= 5

5. Four special slopes:
Positive slope: m>0
Negative slope: m<0

6. Horizontal slope: m=0
Slope is zero
Vertical slope: no slope undefined

7. Slope of parallel lines:
Parallel lines have the same slope but different y-intercepts.
Graph: y = 2x + 2 and y = 2x - 3 on the same graph.

8. = -1 Graph: y = x+3 and y = x -1 on the same graph. 
Perpendicular lines: slopes are the opposite reciprocals of each other
Their product equals -1.
Graph: y = x+3 and y = x -1 on the same graph.
= -1 

9. Show that CEF is a right triangle.
What do I have to prove in order for it to be a right triangle?
(Two sides slopes’ need to be opposite reciprocals in order to have a right angle.)
1. Slope of CE = =
Since the slopes of FE & FC are opposite reciprocals, F is a right . Therefore, CEF is a right triangle.
2. Slope of FE = =
3. Slope of FC = = =