cuboid
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.
A rectangular file is commonly referred to as a "flat file" or "rectangular file." It is a type of hand file characterized by its flat and rectangular shape, used for smoothing or shaping materials, particularly metal and wood. The flat surface allows for effective filing on flat surfaces and edges.
The flat surfaces of all polyhedra are called faces and a rectangular prism is simply one kind of polyhedron.
six
Faces
yes it does.