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.
retangle
Sphere ( 0 faces , 0 edges , 0 vertices )
# of faces + # of edges + # of vertecies + 2
Sphere
According to Euler none; for all 3d shapes: Vertices + Faces = Edges + 2 ⇒ 12 + 8 = 19 + 2 ⇒ 20 = 21 So unless 20 does equal 21, no 3d shape has 8 faces, 19 edges and 12 vertices. Any 3d shape with 8 faces would be an octahedron.
It is a square based pyramid that has 5 faces, 8 edges and 5 vertices
That 3D shape is called triangular pyramid.
cube
a square
Nonahedron
tetrahedron
corn