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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 right.) Bolognese – and the number of tomatoes needed to prepare them. Test the ratios for equivalence and determine whether the relationship is proportional. Well you have a proportional relationship between the number of servings and the number of tomatoes 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 the ratio is 10 to 6, which is the same thing as 5 to 3. So here, the ratio is 5 to 3. Or it's 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 numbers 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.