Proportional Relationships and Constants of Proportionality

Find the rate of change (or constant), and solve for the missing output.

• 27

• 72

• 90

• 88

y in inversely proportional to x, and y = 9 when x = 4.

What is the value of y when x = 3?

*Remember the formula for inverse relationships is y = k/x

• 12

• 4

• 36

• 9

Susan and Joe both insure their properties with the Oklahoma Insurance Company. The cost of house insurance premiums with the Oklahoma Insurance Company is directly proportional to the value of the property being insured.

Susan pays premiums of $80 per month on her property valued at $160,000.

How much does Joe pay on his property valued at $323,000?

• $2,000

• $75.20

• $161.50

• $44.60

The time (t days) required to build a house in inversely proportional to the number of builders (n), all working at the same rate. If there are 8 builders, it takes 90 days to complete the house. How many builders must be employed to build the house in just 20 days?

• 11.25

• 36

• 225

• 70

Is y=kx proportional?

• Yes

• No

• 8

• 4

If two quantities are inversely proportional, what happens to one quantity when the other is halved?

• It remains the same.

• It doubles.

• It halves.

• It quadruples.

Which statement describes the rate of change of the line?

• $20 each week

• $30 each week

• $25 each week

• $70 each week

Match the correct equation to the graph

• y = 4x

• y = 9x

• y = 10x

• y = 3x

y is inversely proportional to x, and y = 15 when x = 3

What is the value of y when x = 9

• There is no solution.

• 45

• 9

• 5