According to gr, the incremental angle of precession in one revolution (one orbit) for a planet (moving about an attractor m) whose orbit is elliptical with semimajor axis a and eccentricity e is given by the formula: that les calculate this precession angle for one orbit of mercury moving about the solar mass m, and find the total precession angle over one hundred years. you will need to look up the values of a, m and ε in mks units