We just multiply times the depth dx. And then if we want to actually find the volume of this entire figure, then we just have to sum up all of these washers for each of our x's. So let's do that. So we're going to sum up the washers for each of our x's and take the limit as they approach 0. But we have to make sure we got our interval right. So what are these? We care about the entire region between the points where they intersect.