There is no regular solid with 13 faces.
A decaredra is the ten face solid figure.
octahedron
They are faces the polyhedron.
A polyhedron (solid shape formed by plane faces) with four faces is called a tetrahedron.
A solid figure with twenty faces is called an Icosahedron.
The regular solid, with 20 identical equilateral triangular faces, is called an icosahedron.
A polyhedron with 20 faces is called an icosahedron.
There is no regular solid with 13 faces.
A four-faced solid is called a tetrahedron.
A polyhedron with 20 faces is called an icosahedron.
Do you mean 'Septenhedral'. If so, that it is a solid object of SEVEN (7) faces.
A tetrahedron.
It is called a Nonagon.
It is called a hexagon because it has six faces and also six vertexes.
They are called faces of the polyhedron.
That's called a Decagon.