A polyhedron is a three-dimensional shape with flat polygonal faces, straight edges, and sharp corners or vertices. A convex polyhedron is a polyhedron that bounds a convex set. Every convex polyhedron can be constructed as the convex hull of its vertices, and for every finite set of points, not all on the same plane, the convex hull is a convex polyhedron. Examples of polyhedra include cubes, prisms, and pyramids. However, cones, spheres, and cylinders are not polyhedra because their sides are not polygons and they have curved surfaces. The parts of a polyhedron are classified as faces, edges, and vertices:
- Faces: The flat surfaces of a polyhedron are called its faces, which are basically polygons.
- Edges: Edges are the line segments where two faces meet.
- Vertices: Vertices are the points where three or more edges meet.
Polyhedra can be classified as prisms, pyramids, and Platonic solids.
