Graphing Proportional Relationships
Equations of Proportional Relationships
Identifying Proportional Relationships
Teacher Sports
100
What is the ordered pair for the origin?
** Don't forget your parentheses around the ordered pair! **
(0,0)
100
Is this equation proportional? y= 3x
If so, what is the constant of proportionality? (K)
Yes
k=3
100
How do you find the constant of proportionality?
Y/X
100
What sport did Mr. Hildredth play?
Football
200
A relationship between two quantities that is changing at a CONSTANT rate is:
a. proportional
b. nonproportional
a. proportional
200
Is this equation proportional? If so what is the constant of proportionality? (K=)
y= 4x + 10
Not proportional
200
Is the graph a proportional relationship? Why?
NO
Does not go through the origin
200
What sport did Mr. Lundy play?
Football
300
What are the two rules to know if a graph is proportional?
1. The line is straight (to show a constant rate)
2. The line goes through the origin (0,0)
300
Is this equation proportional? If so what is the constant of proportionality? (K=)
y= ¾ x
proportional
k= 3/4
300
Is the table proportional?
No
300
What sport did Mr. Hill play?
Track
400
Is this graph proportional? Explain WHY.
Yes, it is a straight line that goes through the origin.
400
Using this graph, What is the equation? Write your constant of proportionality as a FRACTION. 
y= 1/6x
400
Is the table proportional?
Yes it is proportional
400
What sport did Mr. Mernagh never play in an organized league, but played with one of the best players to come out of his home town?
Soccer
500
A recipe for lemonade is given by the equation y = 4x where x represents the cups of lemonade mix and y represents the cups of water.
If Tyler had 16 cups of lemonade mix, how many cups of water would he need for each recipe?
64 cups of water
500
Write an equation for the table given the table is proportional.
y = 3/2 x
or y = 1 1/2x
or y = 1.5x
500
How do you know if a table is proportional?
When you divide the y value with its x value, you get the same constant of proportionality in each row.
500
When Lisa was 6 years old, her sister Lucy was half her age. If Lisa is 40 years old today how old is Lucy?
37 years old.