And as you can imagine, we're going to do this definite integral with respect to y. So what's the volume of this thing? Well, like we did in the last video, we have to figure out the area of the top of each of these disks, or I guess you could say the face of this coin. Well, to find that area, it's pi r squared. If we can figure out this radius right over here, we know the area. So what's that radius? So to think about that radius in terms of y, we just have to solve this equation explicitly in terms of y.