Slice a Pyramid with a Plane to Explore Cross-Section Shapes

This GeoGebra lesson demonstrates how different cross sections of a pyramid are produced by slicing it with a moving plane, highlighting how the cross-section shape changes with the slice’s position and orientation. Key ideas include 3D solids cross sections, the intersection of a plane with a pyramid, and how the resulting polygon type depends on whether the cutting plane is parallel to the base (and what happens as the slice moves farther from the base). The construction uses a pyramid and a parametrically positioned plane (with slider controls), computes the intersection points between the plane and pyramid edges (via tracked face/edge intersection objects), and then forms the cross-section polygon using Polygon. It is appropriate for middle school (Grades 6–8) or introductory solid-geometry exploration where students describe and reason about cross-sectional views.