A polyhedron is a generic term to describe a closed 3-dimensional (solid) shape that is bounded by polygons. It can have 4 or more faces - any number.
3d shapes with plane faces are called polyhedra (singular = polyhedron). The minimum number of vertices is 4, there is no maximum.
Yes: the tetrahedron.
Tetrahedron
A regular polyhedron has equal size faces as in the case of a tetrahedron which is a triangular base pyramid that has 4 equilateral triangle faces.
A polyhedron can have any number of faces 4 or higher.
4
It cannot be a polyhedron since the minimum number of faces for a polyhedron is 4. Also, it does not satisfy the Euler characteristic. I cannot think of a non-polyhedral shape that would meet these specifications.
Yes they normally are as for example a tetrahedron is triangular pyramid that has 4 faces
A polyhedron is a generic term to describe a closed 3-dimensional (solid) shape that is bounded by polygons. It can have 4 or more faces - any number.
3d shapes with plane faces are called polyhedra (singular = polyhedron). The minimum number of vertices is 4, there is no maximum.
Tetrahedron
If you mean a polyhedron then it is true that it can have 4 or more faces
Yes: the tetrahedron.
Tetrahedron
A regular polyhedron has equal size faces as in the case of a tetrahedron which is a triangular base pyramid that has 4 equilateral triangle faces.
Because the Euler characteristic establishes the rule that for all simply connected polyhedra, Faces + Vertices = Edges + 2 Vertices = 4 and Edges = 6 implies that Faces + 4 = 6 + 2 = 8 so that Faces = 4. So there is only one such polyhedron.