## The Best of Demos with Positive Impact

### An Online Resource for Mathematics Instructors

The approximating circular cross sections and the solid generated when a curve is revolved about an axis. The Disk Method is used to set up the integral for computing the volume of the solid of revolution.

The approximating shells and the solid generated when a sine curve is revolved about the y-axis. The Shell Method is used to set up the integral for computing the volume of the solid of revolution.

The approximating disks and washers and the solid generated when a parabola is revolved about the y-axis. The Washer Method is used to set up the integral for computing the volume of the solid of revolution.

The pyramid can be modeled with known cross sections, in this case, square cross sections. The Method of Cross Sections is used to set up the integral for computing the volume of the solid.