Comparing Proportional Relationships

Front

What is a proportional relationship?

Back

A proportional relationship is a relationship between two quantities where the ratio of one quantity to the other quantity is constant.

Front

How can you identify if a relationship is proportional from a table?

Back

If the ratios of corresponding values (y/x) are the same for all pairs, the relationship is proportional.

Front

What is a unit rate?

Back

A unit rate is a comparison of two different quantities when they are combined together, expressed as a quantity per one unit of another quantity.

Front

How do you find the unit rate from a ratio?

Back

To find the unit rate, divide the first quantity by the second quantity to get the amount per one unit of the second quantity.

Front

What does the equation y = kx represent in a proportional relationship?

Back

In this equation, k is the constant of proportionality, which represents the unit rate.

Front

How can you determine which store has a better price using equations?

Back

Compare the equations representing the prices; the store with the lower value for the same quantity has the better price.

Front

What is the constant of proportionality?

Back

The constant of proportionality is the constant value (k) that relates two proportional quantities.

Front

How do you write an equation for a proportional relationship given a graph?

Back

Identify the slope of the line (rise over run) and use it as the constant of proportionality in the equation y = kx.

Front

What does it mean if two quantities are not proportional?

Back

If two quantities are not proportional, their ratios are not constant and change as the quantities change.

Front

How can you represent a proportional relationship using a graph?

Back

A proportional relationship is represented by a straight line that passes through the origin (0,0) on a graph.