Every prism has a 2D face. If it does not, it cannot be a prism.
A pentagonal prism has 7 faces - a prism of any 2D object will have (2D sides + 2) faces.e.g. An octagonal prism - 8 side octagon, 8+2=10 face prism.
A prism, by definition, is 3D. You cannot have a 2D prism.
No.
it a triangle as a 2d shape
The 2D name for an octagonal prism is an octagon. An octagonal prism consists of two parallel octagonal bases connected by rectangular faces, but when referring to its 2D representation, it is simply an octagon.
no, it's 2d
A prism is 3d and a pyramid is in 2d
No. A rectangle is a 2D shape, while a prism is a 3D figure.
You cannot have a 2d prism. The 2d cross section will depend on the plane of the cross section.
The latter
because triangle is only 2d shape but a prism is 3d shape
It is simply called a pentagonal prism. That is a prism based on the 2D shape known as a pentagon.