Proportional Relationships, Ratio Tables, Graphs

Write an equation for this relationship.

• y = 18x

• y = 18.50x

• y = 22.50x

• y = 22x

Which statement about this graph is most true?

• It is proportional

• The cleaner uses 1 cup of vinegar to every 2 cups of cleaner

• The cleaner uses 4 cups of cleaner to 2 cups of vinegar

• All of the above

Is this a proportional equation?  Why?

• It is not proportional because it doesn't have a constant.

• It is not proportional because it doesn't have a constant rate of change.

• It is proportional because if x = 0, y = 0.

• It is proportional because it has a y intercept of 22.

Mr. Diaz changed his shower head to conserve water and energy. The table shows the relationship between the amount of flow and the duration of the water flow.

Which statement BEST describes the rate of water flow?

• 0.4 gallons per minute

• 2.1 gallons per minute

• 2.5 gallons per minute

• 3.0 gallons per minute

Using the data in the table above, how much does 1 gallon of gas cost?

• $3.50

• $4.00

• $4.50

• $5.00

Mason ran 3 miles in 20 minutes. What is his unit rate of miles per hour?

• 400 miles per hour

• 9 miles per hour

• 20 miles per hour

• 6.67 miles per hour

What is the constant of proportionality?

• $3

• $4

• $2

• $9

The table shows a proportional relationship. Which of the following is the equation for the number of cookies, c made with each cup of sugar, s

• s = 12c

• s = 24c

• c = 12s

• c = 24s

Answer explanation

Divide the y value in the ratio by the x value to get the constant.

Remember the top row is the x and the bottom row is the y in the ratio.

Proportional equations are written y=kx where k is the constant of proportionality.

Replace the x and y with variables they represent in the ratio.

Hamburger sells 3 pounds for $6. If Alicia buys 10 pounds of hamburger, how much will she pay?

• $30

• $20

• $60

• $10

A cake recipe calls for 1.5 cups of milk and 3 cups of flour. 

If the cups of milk, x, is compared to the cups of flour, y, what is the equation for y=kx?

• k=2x

• y=0.5x

• k=0.5

• y=2x