A polyhedron is a 3-dimensional shape with MANY, but UNSPECIFIED number of vertices. The number of edges and faces are therefore not specified either. Poly = many Hedron = Vertex
A polygon is a plane (2-dimensional) object bounded by straight lines. A polyhedron (not polyhendron!) is a solid (3-dimensional) object bounded by polygonal faces. So, pyramids and some prisms are polyhedra. A cylinder is a type of prism but, because two of its faces are circular, those faces are not polygons. As a result a cylinder is not a polyhedron.
No, but the faces of a polyhendron are all flat.
If you mean polyhedron - it is solid figure having many faces
A polyhedron is a 3-dimensional shape with MANY, but UNSPECIFIED number of vertices. The number of edges and faces are therefore not specified either. Poly = many Hedron = Vertex
A polygon is a plane (2-dimensional) object bounded by straight lines. A polyhedron (not polyhendron!) is a solid (3-dimensional) object bounded by polygonal faces. So, pyramids and some prisms are polyhedra. A cylinder is a type of prism but, because two of its faces are circular, those faces are not polygons. As a result a cylinder is not a polyhedron.