When revolving a plane region about an axis creates a hole or hollow space in our three-dimensional figure, our rotating representative rectangle creates a washer. Think of that solid as a fresh roll of toilet paper, and the Washer Method must be use to find its volume. This video will succinctly demonstrate that technique. Duration: 3:34

Exercise 6 presents our first usage of the Washer Method. As we did with the Disk Method, we begin by skillfully sketching a graph, a representative rectangle, and its resulting roll of toilet paper. It's highly recommended that you bring one of those with you when take the AP Exam as both a visual reminder of the Washer Method and as a disposable absorption device for any resulting blood, sweat, and/or tears. Duration: 6:01

Our final solid of revolution combines both a disk and a washer. In addition to that complication, we'll be spinning our representative rectangles about the y-axis. Duration: 10:15