Solids with a given cross section
Solids with a given cross-sections
Sometimes students of calculus are requested to calculate the volumes of solids having some given cross section (a square, a triangle, a semi-circle... ).
They often have some problem in visualizing them and their appearance, since a bi-dimensional whiteboard or a sheet of paper doesn't help much.
This applet doesn't address the problem of building the definite integral to be calculated, but can be used as an aid just to help visualizing, in 3D, the solids generated by such rules.
For building the definite integral to be used see:
https://www.math24.net/volume-solid-with-known-cross-section/