Sewanhaka High School
Math 8
Name:________________________________ Per:___
Mrs. Lidowsky, Principal
Mr. Long, Teacher
Date:_____________________
H.W. #21: Ditto
DO-NOW #21: Answer the following questions:
1) Use the table to graph the following ordered pairs
x y Find the constant rate of change.
0 3
4 4
8 5 Is there a proportional linear relationship between the x and
y values? Explain.
2) If -4 was added to the product of -2 and +3, what would the result
be?
3) What is the quotient of -40 and -8?
Topic: Expressions and Equations
Main Idea: Finding Slope
Aim:
RECALL
Compare both hills
NOTES
Which hill is more steep and why?
To compare the steepness of the roads, we compare their slopes.
Find the slope of roads AB and DE .
Refer to the graph from exercise #1 in DO-NOW #21. Label
the point (0, 3) with the letter A, (4, 4) with the letter B, and (8,
5) with the letter C.
What is the ratio of vertical units to horizontal units from point A to
point B?
What is the ratio of vertical units to horizontal units from point A to
point C?
How do the ratios compare?
What is the ratio of vertical units to horizontal units if you want to get
from any point on this line to any other point on this line?
STEPS TO FIND THE SLOPE OF THE LINE:
1) Pick any two points that lie on the line. (ex. (
( , ))
, ) and
2) Find the change in the y-values (vertical change)
3) Find the change in the x-values (horizontal change)
4) Write the ratio of the vertical change to the horizontal change.
5) FINAL FORMULA:
slope of a line ( P1P 2 ) = m =
difference in y values
y
y -y
= 2 1=
difference in x value s x 2 - x 1 x
NOTE: As a point moves from left to right along a line that is rising, y increases as x increases and the slope of the line is positive. As a
point moves from left to right along a line that is falling, y decreases as x increases and the slope of the line is negative.
A hiking trail rises 6 feet for every horizontal change of
100 feet. What is the slope of the hiking trail?
Drill: Answer the following:
Summary:
If time: