Proportional Relationships

Determine the constant of proportionality in the following equation:

y = 8x

• 8

• 18

• 8x

Answer explanation

k is being multiplied by x. Since 8 is the coefficient in the equation, 8 is the constant of proportionality, or k.

Determine k using the table.

• k = 35

• k = 30

• k = 3.5

Answer explanation

Take an ordered pair from the table and plug each coordinate (x and y) into the formula for k.

Tags

CCSS.HSF-LE.A.1B

Which of the following equations best represents this table?

• 35 = 1x

• y = 35x

• y = 3.5x

Answer explanation

Take an ordered pair from the table and plug each coordinate (x and y) into the formula for k.

Tags

CCSS.6.EE.C.9

A restaurant has an all-you-can-eat buffet for $13.95 per person. What is the rate of proportionality?

• $139.50

• $13.95

• It depends on how many people are at the table

Answer explanation

What are they charging per person? If they have 2 people, they would charge them 2 times that number. Etc, etc.

Use the table to determine the constant of proportionality, k.

• 380

• 188

• 95

Answer explanation

Determine k by dividing each y by the corresponding x.

Tags

CCSS.7.RP.A.2B

Which equation best represents the graph?

• y = 50x

• y = 75x

• x = 75y

• y =25

Answer explanation

Find 2 points on the graph that cross at exact points. Take each ordered pair's y and divide it by the ordered pair's x. This is your k.

The formula for the equation is y = kx. You plug in the number you found to represent k FOR k in the equation y = kx.

The points seen are (2 , 150) and (4 , 300).

Tags

CCSS.8.EE.B.5

Which equation best represents this graph?

• y = 50x

• x = 25y

• y = 25x

• x = 50y

Answer explanation

Find a point on the graphed line. Divide y by x to find k. Plug k into the formula y = kx.

Tags

CCSS.8.EE.B.5