So let's figure out how we would do this. Well, we know that all we have to do is figure out what the volume of one of these rings are for a given y as a function of y and then integrate along all of them, sum them all up. So let's figure out what the volume of one of these rings are. And to do it, we're going to express these functions as functions of y. So our purple function, y is equal to square root of x. If we square both sides, we would get y squared is equal to x. Let me swap the sides so it makes it clear that now x is a function of y. x is equal to y squared.