In this fulcrum, for the weights to be balance, what do the distances d1 and d2 have to be if the overall length is 12 feet? d1= 6.55 ft./ 5.45 ft./ 7.20 ft. d2= 5.45 ft./ 6.55 ft./ 4.80 ft.

For this case we have the following system of equations:
 Equilibrium equation:
 60 * d1 = 50 * d2
 Total distance:
 d1 + d2 = 12
 Solving the equations we have:
 d1 = 5.45 feet
 d2 = 6.55 feet
 
 the distances d1 and d2 have to be:
 d1 = 5.45 feet
 d2 = 6.55 feet