Constants of Proportionality

Which graph is proportional?

• A

• B

• C and D

• All of the graphs are proportional

What makes a graph proportional?

• Straight line

• The line goes through the origin

• Curvy line

• Straight line and the line goes through the origin

A box of cereal cost $3.59 for 30 oz. How much is the unit rate per ounce? Round to the nearest cent.

• 11 cents

• 12 cents

• 13 cents

• 10 cents

A proportional relationship can be written as an equation in the form ____ = _____  _____

• y = k+x

• y = k-x

• y = kx

• y = k/x

Identify the constant of proportionality.

• k = 2

• k = 4

• k = 1/2

• k = 1/4

• none (not proportional)

Identify the constant of proportionality.

• k = 5

• k = 1/5

• k = 1

• k = 2.5

• none (not proportional)

Identify the constant of proportionality.

• k = 25

• k = 50

• k = 100

• k = 1/50

• none (not proportional)

Identify the constant of proportionality.

• k = 1/0.45

• k = 0.45

• k = -0.45

• k = -1/0.45

• none (not proportional)

Which of the following statements is TRUE about the graph? Choose all that apply.

• The point (2, 8) shows that 8 pounds of cheese cost$2.00.

• The point (1.5, 6) shows the cost is $6.00 for 1.5pounds of cheese.

• The point (0.75, 3) shows that 0.75 pound of cheesecosts $3.00.

• The point (0.25, 1) shows the cost is $0.25 for 1pound of cheese.

• The point (0, 0) shows the cost is $0.00 for 0 pounds of cheese

Write an equation for this relationship.

• y = 18x

• y = 18.50x

• y = 22.50x

• y = 22x