Setting Up Proportions

Front

What is a proportion?

Back

A proportion is an equation that states that two ratios are equal. For example, if a/b = c/d, then a, b, c, and d are in proportion.

Front

How do you set up a proportion?

Back

To set up a proportion, identify two ratios that you want to compare and set them equal to each other. For example, if you know that 3/4 = x/8, you can set up the proportion.

Front

What is cross-multiplication in proportions?

Back

Cross-multiplication is a method used to solve proportions. If a/b = c/d, then ad = bc.

Front

If 18 out of 30 students have an A, how do you find the total number of students earning an A in a class of 80?

Back

Front

How do you find the number of subscriptions sold over a different time period?

Back

Front

If 16 out of 25 students are boys, how do you find the number of boys in a class of 40?

Back

Front

How do you calculate the cost of hamburger meat based on a given price per weight?

Back

Front

What is the relationship between cost and weight in a proportion?

Back

In a proportion involving cost and weight, you can set up a ratio of cost to weight and use it to find unknown values.

Front

How do you find the number of pounds of gummy bears you can buy for a certain amount of money?

Back

Front

What does it mean if two ratios are equivalent?

Back

If two ratios are equivalent, it means they represent the same relationship between quantities, and their cross-products are equal.