7th Grade Math: Constant of Proportionality

7th Grade Math: Constant of Proportionality

[NC.7.RP.2] I can identify the constant of proportionality using graphs, tables, equations, and verbal descriptions.

What is the constant of proportionality?

• same as the UNIT RATE!

• compares the relationship between two quantities with the second quantity equal to ONE unit.

• symbol: k

Multiple Choice

The constant of proportionality can be found by finding the __________  _____________.

• unit rate
• ratio rate
• proportion answer
• rational number

Multiple Choice

If Justin can type 408 words in 4 minutes, how many words can he type per minute?

• 102 words per minute
• 100 words per minute
• 400 words per minute
• 412 words per minute

Multiple Choice

Which statement best describes the relationship of x and y in the table?

• Proportional
• Not Proportional

Multiple Choice

Does the table show a proportional relationship?

• Yes
• No

Proportionality from a Table

• compare

   $\frac{y}{x}$   ratios

• same? Proportional!

• different? Nonproportional!

Multiple Choice

Does the table represent a proportional relationship?

• Yes.
• No.

Multiple Choice

Does the table represent a proportional relationship?

• Yes.
• No.

Multiple Choice

Determine the missing value in the table.

• 15
• 3
• 1/3
• 9

Multiple Choice

Is the given table a proportional relationship? If so, what is the constant?

• Yes; 1/3
• Yes; 3
• Yes; 5
• No

Multiple Choice

Name the constant of proportionality.

• 20
• 40
• 16
• 35

Proportionality from a Graph

• linear

• passes through the origin

Multiple Choice

Is the graph proportional or non proportional?

• proportional
• non proportional

Multiple Choice

Which graph shows a proportional relationship?

• A
• B
• C
• D

Multiple Choice

What does the point on the graph mean?

• Each pizza costs $20

• Each pizza costs $10

• The pizzeria makes a profit of $1 per pizza

• The pizzeria makes a profit of $10 per pizza

Multiple Choice

In the graph shown, what is the constant of proportionality?

• $50 per hour

• $40 per hour

• $1 per 50 hours

• $100 per hour

Multiple Choice

What is the constant of proportionality for the following graph?

• 80
• 20
• 40
• 160

Multiple Choice

What is k in this proportional relationship?

• 60 
• 120
• 1
• 180

Multiple Choice

The constant of proportionality of this graph is k = 45. What does it mean?

• The boat travels for 45 miles for every 45 hours

• The boat travels 1 mile for every 45 hours

• The boat travels 45 miles for every 1 hour

• The boat travels 1/45 mile for every 1 hour

Multiple Choice

What is the equation for the graph?

• y=½x
• y=2x
• x=2y
• x=½y

Multiple Choice

Name the constant of proportionality.

• 5

• 10

• 2

• 1

Proportionality from Equations

• Remember,

   $k=\frac{y}{x}$  

• So,  $y=kx$  

Multiple Choice

Proportional or Non-Proportional:
The video game rental fee is $15 plus $3 per day. 

• Proportional
• Non-Proportional

Multiple Choice

Shawn makes $7.50 an hour to babysit for his next door neighbors.  Describe the graph of this relationship.

• Proportional
• Non-proportional

Multiple Choice

which has a proportional relationship?

• Hamburgers cost 3.00 plus an additional .50 per topping added.
• You invite your friends to lunch.  It will cost you 5.00 for every guest you bring.
• You get paid 4.00 an hour plus 50.00

Multiple Choice

The constant of proportionality in the equation y = ½x is _______. 

• x
• y
• 1/2
• 2

Multiple Choice

Which is proportional?

• For every friend you bring to the movies it costs $10.00 each.
• A basket started with 300 liters of water has is leaking 5 liters every second.
• A babysitter charges 3.00 per child plus a fee of 20.00.

Multiple Choice

Does this equation represent a proportional relationship?

• Yes

• No

Multiple Choice

Does the equation show a proportional relationship?

• Yes
• No

Multiple Choice

Does the equation show a proportional relationship?

• Yes
• No

Multiple Choice

A cake recipe calls for 1.5 cups of milk and 3 cups of flour. Seth made a mistake and used 5 cups of flour. How many cups of milk should he use to keep the proportions correct?

• 2.5 cups milk
• 1.75 cups milk
• 2 cups flour
• 2.25 cups milk