thunderbird: To learn about the double arrowhead representation of a moment vector, which is much better and easier for your problem, see items 3.5 and especially 3.6 at the bottom of
http://books.google.com/books?id=idWo2Sw_488C&pg=PA72".
cjl: Hint: The mistake you made in your post 16 equation is the most common mistake in algebra, and happens to everyone from time to time. The fact that thunderbird did not make any of this particular kind of mistake is impressive, and indicates thunderbird is quite good in algebra.
thunderbird: If you use other approaches to represent and compute the applied moment at the upper member tip, it is correct only if it produces the same, correct answer. The correct answer begins with Ay = 223.4835 lbf. Please correct me if I am wrong. cjl keeps referring to summing moments about lines passing through a different point than what you used, without realizing yet that the way you already did that part of the problem is the same or similar, cancels out just as many terms, is an excellent approach, and does not produce extra terms. There is no need to change or redo what is already right and in simplest form. Just correct your applied moment in the equilibrium equations you already derived. Therefore, any part of this discussion (from cjl, you, me, whomever) that focuses on how you handle or compute the applied moment at the upper member tip is the only thing you need to focus on and correct.
