Proportional Relationships

Multiple Choice

True or False:

Is the following graph proportional?

• True

• False

Multiple Choice

Is the graph proportional or non-proportional?

• Proportional

• Non-proportional

Multiple Choice

True or False:

Is the following graph proportional?

• True

• False

Poll

Do you understand if a graph is proportional or non-proportional?

• yes

• no

In a proportional relationship, the values for one quantity are each multiplied by the same number to get the values for the other quantity. This number is called the constant of proportionality.

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The constant of proportionality is our unit rate for the relationship.

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Constant of Proportionality

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​y / x = 15 / 5 = 3

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The constant of proportionality is 3.

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What does the constant of proportionality mean?

You can paint 3 birdhouses with 1 can of paint. ​

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Tables are Proportional When...

• The ratios of the numbers in the table are equivalent, the relationship is proportional. 

  
  

What is important to know about proportional relationships?

• They are represented by equivalent ratios between the input and output values.

• Can be used to calculate unit rate.

What is a proportional relationship?

• A proportional relationship is a relationship in which the ratio between the two quantities is equivalent for all values.

• The table to the right represents a proportional relationship...

Constant of Proportionality

• All proportional relationships have constant ratio, which is called the unit rate.

• ​​In the table to the right, the unit rate can be found by dividing the distance by the time.

Multiple Choice

Does the table represent a proportional relationship?

• Yes.
• No.

Multiple Choice

What is the constant of proportionality for this table?

• 1/9
• 9
• 8

Multiple Choice

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

• Yes; 1/3
• Yes; 3
• Yes; 5
• No

You know equations are poroportional when...

• The y-intercept is 0. This means that it is on the origin!