A body is in equilibrium when three forces are working in on it. Two forces is shown... A and B 68N and 50N with a 45 degrees. A third force F is not shown. Determine by means of a triangle of forces the magnitude and direction of the third force F.

Use the fact that the sum of forces in the horizontal direction must equal zero, as must the sum of forces in the vertical direction. This will give you the magnitudes of the components of force F in the horizontal and vertical directions. Can you take it from here?