A 3D shape with all straight edges and flat faces is a polyhedron. Other 3D shapes with least one curved surface are not polyhedra. A 3D shape with regular polygonal faces, meeting at equal angles, is ...

A well-known example of a prism is a cylinder and you can see from the image above that the front face (cross-section) is the same size of circle no matter where you slice it. The formula for the ...