Step-by-step explanation:
A cross section of a prism will match the base of the prism when the plane of the section is parallel to the base.
If the polyhedron is not a prism, or the lateral faces are not perpendicular to the base, or the plane of cross section is not parallel to the base, you can get a variety of cross-section shapes.
For example, the cross sections of a cube include ...
triangle, square, rectangle, trapezoid, general quadrilateral, pentagon, hexagon