The question is ambiguous since a rectangular pyramid and a rectangular prism will have different numbers of flat surfaces. There is no indication in the question which shape is intended.
rectangular prism
A rectangular shape has 6 flat sides. Those sides are the top, bottom, front, back, left and right,
A cube or a rectangular prism.
A "rectangular" is an adjective, not a noun and so there is no way of knowing what the shape is. It could be a rectangular 2-d shape, a rectangular pyramid, a rectangular prism and they would all have different answers.
A rectangular prism has 6 flat surfaces
It has 6 faces which are its flat surfaces.
The flat surfaces of all polyhedra are called faces and a rectangular prism is simply one kind of polyhedron.
six
Faces
6
yes it does.