Ratios, Unit Rates, and Proportions

Front

What is a ratio?

Back

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

Front

What is a unit rate?

Back

A unit rate is a ratio that compares a quantity to one unit of another quantity, expressed as 'per 1'.

Front

How do you calculate a unit rate?

Back

To calculate a unit rate, divide the quantity by the number of units. For example, if you have 408 words in 4 minutes, divide 408 by 4 to find the words per minute.

Front

What is a proportion?

Back

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

Front

How can you determine if two ratios form a proportion?

Back

Two ratios form a proportion if the cross products are equal. For example, if a/b = c/d, then ad = bc.

Front

What is the formula for finding miles per gallon?

Back

Miles per gallon (mpg) = Total miles driven / Total gallons of gas used.

Front

If a pizza costs $97.50 for 15 pizzas, how do you find the unit cost per pizza?

Back

To find the unit cost, divide the total cost by the number of pizzas: $97.50 / 15 = $6.50 per pizza.

Front

What is the difference between a rate and a unit rate?

Back

A rate is a ratio that compares two different units, while a unit rate compares a quantity to one unit of another quantity.

Front

If Anna types 408 words in 4 minutes, how many words does she type in 1 minute?

Back

Anna types 102 words per minute.

Front

What does it mean if two ratios are not a proportion?

Back

If two ratios are not a proportion, it means that their cross products are not equal.