The answer <span>the third rope to counterbalance Sam and Charlie is F and vectF +vectF1 +vectF2 =vect0 let's consider axis y'y </span>vectF = -F vectF 1= F1cos60 vectF 2= F2cos45 -F = -F1cos60-F2co45 so F= F1cos60+F2co45= 350x0.5+400x0.7=457.84 pounds