1. The problem statement, all variables and given/known data Hi everyone, I've been stuck on this relatively very simple problem for quite a while now and even after solving I'm still getting two answers while the book only lists one. Question: If block D weighs 300 lb and block B weighs 275 lb, determine the required weight of block C and the angle (theta) for equilibrium. So I did the usual since it's in equilibrium then Fx = 0 and Fy = 0. So, Fc(cos30) - 275(cos[itex]\theta[/itex]) = 0 and Fy(sin30) + 275(sin[itex]\theta[/itex]) - 300 = 0 Then after finding cos[itex]\theta[/itex] in terms of Fc and substituting, you get this equation: 158.7cos[itex]\theta[/itex] + 275sin[itex]\theta[/itex] = 300 The answer listed is: [itex]\theta[/itex] = 40.9 and Fc = 240lb Can anyone please tell me how to solve the equation above? I tried using the trig identity (square of cos plus square of sin = 1) but I got two answers, one was similar to the book ([itex]\theta[/itex] = 40.9, and one was [itex]\theta[/itex] 79). Thing is, when I use the second value I got (79) in the equations above, it works for all. I'd appreciate some clarification on this problem! Thanks.