Proportional Relationships

Proportional Relationships

by B. Cox

​What is a proportional relationship?

​Two variables, x and y, have a proportional relationship if:

​

​y is a constant multiple of x

​

​The constant multiple is known as the

constant of proportionality.

​Constant of Proportionality

​Equations of Proportional Relationships

​Example

​Example

​Example

Multiple Choice

In a proportional relationship, when $$x=6$$  , $$y=42$$  .

Which of the following equations represents this relationship?

• $$y=5x+12$$  

• $$y=8x-6$$  

• $$y=7x$$  

• $$y=\frac{1}{7}x$$  

Fill in the Blank

In a proportional relationship, when $$x=6$$  , $$y=42$$  .

What is the y-value when $$x=10$$  ?

Multiple Choice

In a proportional relationship, when $$x=8$$  , $$y=3$$  .

Which of the following equations represents this relationship?

• $$y=x-5$$  

• $$y=\frac{8}{3}x$$  

• $$y=\frac{1}{2}x-1$$  

• $$y=\frac{3}{8}x$$  

Fill in the Blank

In a proportional relationship, when $$x=8$$  , $$y=3$$  .

What is the y-value when $$x=16$$  ?

Multiple Choice

In a proportional relationship, when $$x=10$$  , $$y=15$$  .

Which of the following equations represents this relationship?

• $$y=x+5$$  

• $$y=\frac{3}{2}x$$  

• $$y=2x-5$$  

• $$y=\frac{2}{3}x$$  

Fill in the Blank

In a proportional relationship, when $$x=10$$  , $$y=15$$  .

What is the y-value when $$x=2$$  ?