Analyzing Proportional Relationships

What makes a graph proportional?

• Linear (straight line), that does NOT go through the origin.

• A straight line (linear) that goes through the origin

y=kx.  What does the k represent?

• constant of proportionality

• multiplier

• scale factor

• all of these are correct

Which has a greater constant of proportionality according to the graph above?

• Avenger

• Serendipity

• Both have the same

Sharon uses the services of the Connect-Us Phone Company. This company charges $0.10 per minute for phone calls within the United States. Which graph expresses the relationship between the number of minutes and the corresponding cost?

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The graph shown compares the number of feet equal to a given number of yards. Which equation correctly shows the rate of change?

• y=3x

• y=1/3x

• 3=yx

• x=3y

Identify the constant of proportionality. Write your answer as y=kx

• y=14x

• y=7x

• y=2x

• y=6x

Identify the constant of proportionality. Write your answer as y=kx

• y=6x

• y=54x

• y=9x

• y=5x

For the equation: k=y/x, the variable k is called the...

• Constant, and it represents the constant rate of change or constant ratio between x and y

• Variable, and it represents the constant rate of change or constant ratio between x and y

• x factor, and it represents the constant rate of change or constant ratio between x and y

• y factor, and it represents the constant rate of change or constant ratio between x and y

Craig earns extra money as a lifeguard. He earns $37 for 4 hours and $64.75 for 7 hours.  What is the constant of proportionality (unit rate)? 

• $37

• $64.75

• $9.25

• $18.50

Write an equation for this situation.

• y=9.75x

• y=19x

• y=19.25x

• y=9.5x