Hexagonal prism.
cylinder
Cylinder
It is an octagonal prism
it is a decogonanon it is a decogonanon
rectangular prism
# of faces + # of edges + # of vertecies + 2
Yes, and three rectangular faces.
cylinder: 3 faces, 2 edges, no vertex
a cylinder
Prism
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.
A believe this is a cylinder (like the shape of a can), but there might be others.