S - Ratios and Proportions Lesson

Ratios and Proportions

Throughout this module and the next, it will be important to be able to set up and solve proportions correctly.  

A ratio is a comparison of two numbers using division. You may have seen them written with a colon, but generally in math class we write them as a fraction. You have seen this in the grocery store. Stores will often try to entice you to buy more by pricing items using ratios like, four for a dollar (4/$1) or three for 5 dollars (3/$5). Twelve packs of soda might be on sale for three for ten dollars (3/$10).

A proportion is a statement that two fractions are equal. Proportions are often used to find more information, when ratios are involved.

Suppose candy was listed as 2/$3 and you wanted to know how much that was for 9 packs.

Image of pricing: 2 items for $3.00

Perhaps veggies are on sale for 4/$5 and you want to buy 5.

Image of pricing: 4 items for $5.00

Maybe you are having some friends over and you want to buy three 12 packs of soda and they cost 4/$9.

Ratios4for9.jpeg

Check out the video below for an explanation of how these proportions can be set up and solved for the missing values.

Proportions Activity

Now practice by solving the following proportions on your own.

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