1. The problem statement, all variables and given/known data [PLAIN]http://img808.imageshack.us/img808/2293/asdfkn.jpg [Broken] 3. The attempt at a solution If I look at the left triangle, the answer is obvious. The angle IHF will be 180-35 = 145deg, thus the angle IFH will be 180-20-145 = 15deg. Then using sine rule, sin15/4 = sin20/(FH), thus FH = 4sin20/sin15. My problem though is how come I can't find the right answer if I use the triangle on the right? If I do sin35/9 = sin(a)/12 where a is angle HFG, this leads me to a = 50 degrees. Thus angle FGH is 180-49.89-35 = 95 degrees. Then using sine rule again: sin95/FH = sin35/9 Leads to FH=9sin95/sin35 = 15.63. From what I gathered, this descreptancy is due to the ambiguous case. I've read up on wiki, but I'm not entirely sure about the exact details of such a situation. Can anybody show how to get the correct answer using the triangle on the right?