So hopefully we can visualize this. We've done this several times already, attempting to visualize these shapes. But let's think about how we could actually figure out the volume of this solid of revolution. Well, let's just think about it disk by disk. So let's construct a disk right over here. And we've done this many, many, many times already, where we essentially want the volume of each of these disks, and then we're going to take this for each of these x's in our interval, and then we're going to take the sum of the volumes of all of the disks and we're going to find the volume. We're going to stack them all up, or I guess put them next to each other in this case, and find the volume of our entire figure.