Ratios, Proportions, Constant of Proportionality

Front

What is a ratio?

Back

A ratio is a comparison of two quantities, showing how many times one value contains or is contained within the other.

Front

How do you write a ratio?

Back

Ratios can be written in three ways: as a fraction (1/5), with a colon (1:5), or with the word 'to' (1 to 5).

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal.

Front

How do you solve for an unknown in a proportion?

Back

Cross-multiply the ratios and then solve for the unknown variable.

Front

What is the constant of proportionality?

Back

The constant of proportionality is the constant value (k) that relates two proportional quantities, often represented as y = kx.

Front

If the ratio of cups of sugar to cups of flour is 1:5, how much sugar is needed for 25 cups of flour?

Back

5 cups of sugar.

Front

What is the unit rate?

Back

The 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

What is the unit rate for 120 miles in 2 hours?

Back

60 miles per hour.

Front

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

Back

A relationship is proportional if the ratios of the corresponding values are equivalent.

Front

What does it mean if a graph represents a proportional relationship?

Back

It means that the graph is a straight line that passes through the origin (0,0).