Description: A ratio is a comparison of two quantities. Learn how to find the ratio between two things, for example apples to oranges. Created by Sal Khan. We've got some apples here and we've got some oranges and what I want to think about is, what is the ratio, what is the ratio of apples? But we don't have to just satisfy us with this because one way to think about ratios, especially if we're thinking about apples to oranges, is how many apples do we have for a certain number of oranges? When you think about it that way, we can actually reduce these numbers, as you might have already thought about.*Teacher Advisor is 100% free.