A rectangular pyramid is a solid (3-dimensional) figure that comes to a point opposite the base (like the Pyramids of Egypt.) Its base is a four-sided plane figure with right angles and opposite sides equal (a rectangle--or square for that matter).
Square pyramid
You are a pyramid!
cone that is my answer
I believe it is a cone, if you are intending for us to tell you the 3d figure.
A rectangular pyramid is a solid (3-dimensional) figure that comes to a point opposite the base (like the Pyramids of Egypt.) Its base is a four-sided plane figure with right angles and opposite sides equal (a rectangle--or square for that matter).
Parallelepipedal, approximatively
a square pyramid, perhaps a rectangural prism with a square pyramid on top
No. A flat, 2-dimensional figure can be a quarilateral - a square for instance. A 3-dimensional figure like a sugar cube, which is a solid and has thickness, cannot. For solid shapes, names like 'Parallelepiped and rhombohedron' are used.
Square pyramid
You are a pyramid!
Sphere.
A polygon is a many sided 2-dimensional figure, and thus could never be "solid" Alternatively, it could be "one face that is a polygon". In that case the solid could be like a pyramid that morphs into a cone or a part-sphere. The base would be the one polygon, the other face would not.
A three dimensional solid figure looks like a cube or a prism. Pyramids are three dimensional solid figures as well.
By the shape...
Rectangular prism
cone that is my answer