So one way that we can do this is that we can come up with a relationship between the volume at any moment in time and the height at any moment in time, and then maybe take the derivative of that relationship, possibly using the chain rule, to come up with a relationship between the rate at which the volume is changing and the rate at which the height is changing. So let's try to do it step by step. So first of all, can we come up with a relationship between the volume and the height at any given moment? Well, we have also been given the formula for the volume of a cone right over here. The volume of a cone is 1 third times the area of the base of the cone times the height. And we won't prove it here, although we could prove it later on, especially when we start doing solids of revolutions in integral calculus. But we'll just take it on faith right now that this is how we can figure out the volume of a cone.