7th 2-4 Constant of Proportionality

A recipe calls for 3 ounces of flour(x) for every 2 ounces of sugar(y). Find the constant of proportionality.

• 2/3

• 3/2

• 5

• 6

You bike 11.2 miles in 1.4 hours at a steady rate. What equation represents the proportional relationship between the x hours you bike and the distance y in miles that you​ travel?

• 9

• 8

• .125

• .135

Water is steadily dripping from a faucet into a bowl. You want to write an equation that represents the number of milliliters y of water in the bowl after x seconds. What is the constant of proportionality for the relationship between the number of milliliters y of water in the bowl and the time in seconds​ x? What is the​ equation?

• $y=15x$
  

• $y=\frac{1}{16}x$
  

• $y=16x$

• $y=\frac{1}{15}x$
  

Suppose the relationship between x and y is proportional. When x is​ 29, y is 275.5. Find the constant of proportionality of y to x. Use the constant of proportionality to find x when y is 408.5.

• 43

• 3,880.75

• 45

• 3,909.25

The width of a row of identical townhouses is in a proportional relationship with the number of townhouses. The diagram suggests a row of 5 townhouses and gives their total width.Use the constant of proportionality to find the width of a row of 9 townhouses.

• 169

• 179

• 189

• 199

A family on vacation took a road trip to Florida. Use the table to determine whether an equation in the form y=kx can be written for the situation. Explain your answer.

• Yes. Since the value of the ratio y/x is the same for each pair of​ values, the relationship is proportional.​ So, an equation can be written for the situation.

• Yes. Since the​ y-values in the table increase at a constant​ rate, the relationship is proportional.​ So, an equation can be written for the situation.

• No. Since the value of the ratio y/x is the same for only two pair of​ values, the relationship is not proportional.​ So, an equation cannot be written for the situation.

• No. Since the​ x-values in the table do not increase at a constant​ rate, the relationship is not proportional.​ So, an equation cannot be written for the situation.

Mental Math: An engineer makes​ different-size samples of a new material. The table shows volumes and the related masses. What would be the mass of 100 cubic centimeters of the​ material?

• 10,000

• 100

• 1000

• 10

The number of pizzas is in a proportional relationship to the weight of the shredded cheese toppings. When​ shredded, a​ 50-lb block of cheese is enough to make 150 large pizzas. How much cheese is on one slice of pizza if there are 8 slices per pizza.

• .042 lb

• .375 lb

• .025 lb

• .062

For every 3 lemons you buy at a farm​ stand, the total cost increases by​ $1.80. What is an equation that relates the total cost y and the number of lemons x.

•  $y=.6x$  
  

•  $y=1.67x$  
  

•  $y=3x$  
  

•  $y=1.80x$  
  

For every dozen bagels you​ buy, the cost increases​ $15. Write an equation that represents the cost y and the number of bagels x.

•  $y=.8x$  
  

•  $y=1.25x$  
  

•  $y=12x$  
  

•  $y=15x$