The question is ambiguous. An octagon is a 2-dimensional shape with 8 edges and 8 vertices. Does a 3-D octagonal shape mean one with 8 edges or 8 faces or vertices, or faces which are 2d octagons?
the vertices are the corners to the shape, so you count the corners to whatever shape.
It is a square based pyramid which has 5 faces, 8 edges and 5 vertices
tricontatetrahedron
A polyhedron (solid shape formed by plane faces) with four faces is called a tetrahedron.
FacesE.g. Faces of a cube
There is not a polyhedron with the given number of faces, edges and vertices.
then it's a - Dodecahedron
the shape that has 8 faces , 18 edges , and 12 vertices is simply a hexagonal prism not a pyramid my butt :P
An octahedron is a polyhedron with eight faces, twelve edges, and six vertices
There is no 3-d shape with 4 and 1 = 5 triangular faces.
The question is ambiguous. An octagon is a 2-dimensional shape with 8 edges and 8 vertices. Does a 3-D octagonal shape mean one with 8 edges or 8 faces or vertices, or faces which are 2d octagons?
It is a cube or a cuboid which also has 12 edges and 8 vertices
Triangular prism
A parallelepiped, of which a cube is a special case.
triangular prism
It is a triangular based pyramid which is called a tetrahedron