ACTA PHYSICA SLOVACA, cilt.54, sa.3, ss.221-232, 2004 (SCI-Expanded)
After presenting Clifford algebra and quaternions, the symmetry operations with Clifford algebra and quaternions are defined. This symmetry operations are applied to a Platonic solid, which is called as dodecahedron. Also, the vertices of a dodecahedron presented in the Cartesian coordinates are calculated.