Many, an unspecified number. Poly, in Greek, means many. Polyhedra (singular polyhedron) means "many faced".
Decahedron
There are only 5 regular polyhedra: those with 4, 6, 8, 12 and 20 faces. If you know of 7 polyhedra there may be a Fields Medal (the Nobel prize for mathematicians) for you!
dodecahedron
dodecahedron
A twelve-faced shape is a dodecagon, also known as a dodecahedron.
A dodecahedron is a twelve-faced polyhedron.
They are all polyhedra with 12 edges.
Polyhedra are named by the number of faces they contain. The names are based on Classical Greek. Over time, some polyhedra have become known by common, non-Greek names, i.e. a regular hexahedron is commonly called a cube.
They are polyhedra, each with a square base.They are polyhedra, each with a square base.They are polyhedra, each with a square base.They are polyhedra, each with a square base.
NO, but prisms are polyhedra. Polyhedra include a lot more shapes than just prisms.
No. A pyramid is a polyhedron. Many pyramids are polyhedra.