A recipe calls for 3 cups of sugar for every 1 cup of butter. How many cups
of butter does the recipe need for 4.5
cups of sugar?

1.5 cups of butter

Step-by-step explanation:

3 : 1 <- this is our ratio

divide by 2

1.5 : 0.5 is our new ratio

equation: 1.5 * ? = 4

? = 3 cups of sugar

multiply the ratio by 3

1.5 : 0.5 = 4 : 1.5

we need 1.5 cups of butter for 4.5 cups of sugar

go on the tube you might find some information there