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## Pre-algebra

### Course: Pre-algebra>Unit 9

Lesson 4: Identifying proportional relationships

# Proportional relationships: spaghetti

Given a table of ratios, watch as we test them for equivalence and determine whether the relationship is proportional. Created by Sal Khan.

## Video transcript

The following table describes the relationship between the number of servings of spaghetti bolognese-- I don't know if I'm pronouncing that-- or bolognese, and the number of tomatoes needed to prepare them. Test the ratios for equivalents, and determine whether the relationship is proportional. Well, you have a proportional relationship between the number of servings and the number of tomatoes is if the ratio of the number of servings to the number of tomatoes is always the same. Or if the ratio of the number of tomatoes to the number of servings is always the same. So let's just think about the ratio of the number of tomatoes to the number of servings. So it's 10 to 6, which is the same thing as 5 to 3. So here the ratio is 5 to 3. 15 to 9, if you divide both of these by 3, you get 5 to 3. So it's the same ratio. 15 to 25, if you divide both of these by 5, you get 5 to 3. So based on this data, it looks like the ratio between the number of tomatoes and the number of servings is always constant. So yes, this relationship is proportional.