1. The problem statement, all variables and given/known data In the figure F1= 27.9KN, F2= 39.8KN, F3= 61.8KN What distance d is required for the net couple moment on the triangle to be 1140 counterclockwise? Express your answer to three significant figures and include the appropriate units. link to image http://imgur.com/cBnLJ 2. Relevant equations I'm thinking the only really relevant equation is Mc=rXf or Mc=|r||F|sin(theta) 3. The attempt at a solution So I wrote each moment in terms of d using trig. I got: Mf1= 27900d Nm Mf2= 19900d Nm Mf3= 61800cos(30)d Nm Then I set the sum of the three moments (with direction taken into respect) equal to 1140 Nm. 1140 = 11900d + 61800cos(30)d - 27900d d~= 0.03038 m or 3.04*10^-2 m. Unfortunately this was wrong and I have no clue where I went wrong. Any help would be greatly appreciated.