A regular icosahedra is a regular polyhedron formed by $$20$$ equal equilateral triangles.
If we develop the icosahedra, we obtain the following figure:
The properties of the octahedron are:
- Number of faces: $$20$$
- Number of vertexes: $$12$$
- Number of edges: $$30$$
- Number of edges meeting in each vertexes: $$5$$