It is not clear what the question means since a pentagon must be a 2-d shape.
a pentagon.... it is pretty self explanatory.
In 2-d a pentagon, in 3-d a rectangular pyramid.
It depends on what you mean by a 3-d pentagon. To most people, a 3-d pentagon is a dodecahedron - a 3d shape with 12 pentagonal faces. In that case, each of the faces, by definition, must be a pentagon! If you mean a pentahedron - a 3d shape with 5 plane faces, it could be a triangular prism or a quadrilateral based pyramid. In the first cae the bases are triangles, in the second, a quadrilateral.
A dodecahedron is a 3-d shape with 12 faces that are regular pentagons.
A pentagon is a 2-D shape. You can't find the volume of it unless it's 3-D. The formula for the area of a pentagon has something to do with the perimeter, the number of sides, the apothem, and the number 2.
A square pyramid.
A pentagon is a 2-D shape. There is a 3-D shape with 12 faces, each a regular pentagon. It's called a dodecahedron. To make one out of (stiff) paper, you would cut out a "net", then fold and glue the edges. See related link for an illustration of a net you could print out.
a pentagon
A 3-D pentagon
I'm assuming you mean a 3-d shape with faces of pentagons. This is called a Dodecahedron
A 3-d shape made from pentagonal faces is a dodecahedron (12 sides).