The mathematical expression of the entropy valid for a quantum, relativistic and gravitational phenomenon must explicitly contain the Planck constant h/2pi, the velocity of light in vacuum c and Newton gravitational constant G. Besides this the entropy, as a thermodynamics and statistical concept, must also explicitly contain Boltzmann constant k. Starting from these ideas we are able to calculate Hawking's entropy valid for black holes in N dimensions. In order to calculate Hawking's entropy we use the following ingredients: (i) the methods of dimensional analysis; (ii) the connection between entropy and information; and (iii) the holographic principle.
Hawking's entropy; dimensional analysis; black holes
