It is well known the method of determining the center of mass of a triangular piece in which it is hanged from each one of its vertices while drawing from the vertice its verticals. The intersection of the three verticals is considered as the center of mass, verified by equilibrating the piece over a point object. But not everybody knows that the method was developed by Arquimedes 2,300 years ago, determining the geometrical elements to the medians of the triangle. He demonstrated theoretically its result and, inspired on his demonstration we developed another one, which lends to the ideia and methods of the differential and integral calculus.

Comment: 10 pages, in Portuguese, 14 figures