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 do you find the total amount sold in a proportional relationship?

Back

Multiply the rate of sale by the time period. For example, if 16 hot dogs are sold per minute, in 30 minutes, 16 x 30 = 480 hot dogs.

Front

If there are 3 boys for every 5 girls, how do you find the number of boys if you know the number of girls?

Back

Use the ratio to set up a proportion. If there are 70 girls, then (3/5) = (x/70), where x is the number of boys. Solve for x to find 42 boys.

Front

What is the formula to calculate unit rate?

Back

Unit rate is calculated by dividing the total amount by the number of units. For example, if Samantha earned $90 for 6 hours, her rate is $90/6 = $15 per hour.

Front

How do you determine the cost of multiple items in a proportional relationship?

Back

Set up a ratio based on the cost of a known quantity. If 3 cookies cost $2.00, then 15 cookies cost (15/3) x $2.00 = $10.

Front

What does it mean if two quantities are in a constant ratio?

Back

It means that as one quantity increases or decreases, the other quantity does so in a way that maintains the same ratio.

Front

How can you express a proportional relationship using an equation?

Back

A proportional relationship can be expressed as y = kx, where k is the constant of proportionality.

Front

What is the constant of proportionality?

Back

The constant of proportionality is the factor by which one quantity is multiplied to obtain the other quantity in a proportional relationship.

Front

If a bag of trail mix has 2 M&Ms for every 10 raisins, how do you find the number of raisins if you know the number of M&Ms?

Back

Set up a proportion: (2 M&Ms / 10 raisins) = (18 M&Ms / x raisins). Solve for x to find 90 raisins.

Front

What is the relationship between ratios and proportions?

Back

Ratios compare two quantities, while proportions state that two ratios are equal.