Constant of Proportionality with Tables, Equations and Graphs

What makes a graph proportional?

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

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

The equation y = 4.3x can be used to determine the total cost, y, in dollars, of x pounds of apples.  What does the number 4.3 represent in the equations?

• The number of apples in x pounds

• The cost of x pounds of apples

• The cost of 1 pound of apples

• The number of apples in 1 pound

What is the unit rate for the table?

• $1 / 3 watermelon

• $3 / 1 watermelon

• 1/3 watermelon / pound

• $0.33 / 1 watermelon

Does the following table represent a proportional relationship? If so identify the constant of proportional and create an equation to represent it.

• Proportional; k = 1/40 pages per day; y=1/40x

• Proportional; k = 40 pages per day; y=40x

• Not Proportional

• Proportional; k = 40 days per pages; y=40x

Does the following table represent a proportional relationship? If so, identify the constant of proportionality and create an equation to represent it.

• Proportional; k=8; y=8x

• Not Proportional

• Proportional; k = -8; y=-8x

• Proportional; k=1/8; y=1/8x

What makes a graph proportional?

• It is a straight line.

• It goes through the origin.

• It does not go through the origin.

• If it goes down instead of up.

Which of the following tables are proportional? (You may select more than one!)

• 
• 
• 

Is this table proportional?

• Yes

• No

Which graph is non-proportional?

• A

• B

• C

• D

Which equation would math this proportional relationship?

• y = 45x

• y = 15x

• y = 30x

• y = 20x