Three cables pull on the pipe such that they create a resultant force having a magnitude...

Three cables pull on the pipe such that they create a resultant force having a magnitude of 900 lb. If two of the cables are subjected to known forces, as shown in the figure, determine the angle θ of the third cable so that the magnitude of force F in this cable is a minimum. All forces lie in the x-y plane. What is the magnitude of F? Hint: First find the resultant of the two known forces.