And then let me just shade it in a little bit to give you a little bit of the depth. So how can we find the volume of this? Well, like any disk or cylinder, you just have to think about what the area of this face is and then multiply it times the depth. So what's the area of this face? Well, we know that the area of a circle is equal to pi r squared. If we know the radius of this face, we can figure out the area of the face. Well, what's the radius?