Proportional Relationships and Direct Variation

The __________________ is the constant ratio of the x and y values in a proportional relationship.

• Slope

• Constant of coordinates

• Constant of proportionality, also called the constant of variability

• y-intercept

What is the variable that is used for the constant of variability?

• y

• x

• m

• k

How do you calculate the constant of variability, k?

The constant of proportionality is used for what kind of relationships?

• All linear relationships

• Non-proportional linear relationships

• Linear proportional relationships

• There is no such thing as a constant of proportionality

In a proportional relationship the constant of variability (k) is like the _______.

• Slope

• y-intercept

• x-coordinate

• y-coordinate

In a linear relationship, ________ is often a y-value.

• Time

• Money

In a linear relationship, ________ is often a x-value.

• Time

• Money

How can you solve a problem involving direct variation?  Choose ALL answers that apply.

• Plug the values into y = mx + b
  

Michael earns $28.50 for three hours of tutoring. How much money will Michael earn for 8 hours of tutoring?

• $9.50

• $228

• $76

• $3.56

Look at the table. What is k, the constant of variation?

• 0.083

• 35

• 560

• 1