Grados  = Pi/180;
p =  87.0;
n = 72.0;
M =  (35  +  18/60  +  
              46/3600) Grados;
m  =  
        Sqrt[(p^2) + (n^2) - 2 p n Cos[M]];
S  =  (1/2) p n Sin[M];
angA  =  45.0 Grados;
angB =  15.0 Grados;
angC = 120.0 Grados;
c = (Sqrt[((2 S Sin[angC])/(Sin[angA] Sin[angB]))]); 
    Print["c=", c];