It is an octahedron that is a 3D shape with 8 faces
octagon
That 3D shape is called triangular pyramid.
A 3D 5 sided shape is called a dodecahedron. It is a solid with 20 vertices, 30 edges and 12 equal pentagonal triangular faces.
cube
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.
Hexagonal prism
a square
It is a cuboid
It is an octahedron that is a 3D shape with 8 faces
i would say a cube
A hexagonal based prism.
A hexagon based pyramid.
Not too sure but you may be thinking of a cube which has 6 same flat faces, 12 edges and 8 vertices
retangle
pyramid
octagon