How come a three-dimensional figure with a curved surface is not a polyhedron?
2 Answers
Mar 26, 2016
Polyhedron, by definition, is formed by intersecting planes, so each part of its surface is either a vertex or an edge, or a flat piece of a plane.
Explanation:
The definition of polyhedron implies that each side is a piece of a flat surface.
Mar 28, 2018
Each face of a polyhedron is a polygon, which by definition is a two dimensional closed shape, bounded by straight lines.
Therefore a circle is not a polygon,
In the same way, the faces of a polyhedron (a three-dimensional figure) have to be planes with straight edges,
A cylinder and a cone are therefore not considered to be polyhedra because they have curved surfaces.