Ratios review

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

How do you write a ratio?

Back

Ratios can be written in three ways: using a colon (e.g., 2:3), as a fraction (e.g., 2/3), or with the word 'to' (e.g., 2 to 3).

Front

What is a unit rate?

Back

A unit rate is a ratio that compares a quantity to one unit of another quantity, often expressed as 'per' (e.g., miles per hour).

Front

How do you find the unit rate from a total cost and quantity?

Back

To find the unit rate, divide the total cost by the quantity. For example, if 4 pounds of grapes cost $15, the unit rate is $15 ÷ 4 = $3.75 per pound.

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. It can be solved by cross-multiplying.

Front

How do you set up a proportion?

Back

To set up a proportion, write two ratios as fractions and set them equal to each other. For example, if Adam gained 6 pounds in 2.5 months, the proportion for 6 pounds/2.5 months = x pounds/6 months.

Front

What does cross-multiplying mean?

Back

Cross-multiplying involves multiplying the numerator of one fraction by the denominator of the other fraction to find a solution in a proportion.

Front

How do you calculate the total cost from a unit rate?

Back

To calculate the total cost, multiply the unit rate by the quantity. For example, if the unit rate is $3.75 per pound and you buy 4 pounds, the total cost is $3.75 × 4 = $15.

Front

What is the ratio of bananas to total pieces of fruit if there are 2 bananas, 5 apples, and 8 oranges?

Back

The ratio of bananas to total pieces of fruit is 2:15, since there are 2 bananas and a total of 15 pieces of fruit (2 + 5 + 8 = 15).

Front

How do you find the total amount spent over a period of time using a monthly expense?

Back

To find the total amount spent, multiply the monthly expense by the number of months. For example, if Mary spends $246 in 3 months, her monthly expense is $246 ÷ 3 = $82, and over 5 months, she will spend $82 × 5 = $410.