1. The problem statement, all variables and given/known data Solve triangle having indicated sides and angles. a=6 b=9 C=45degrees 2. Relevant equations Law of Cosines Law of Sines 3. The attempt at a solution I did c^2=9^2+6^2-(2*9*6*Cos45 degrees) c=6.37 ... Then I did 6.37/cos45 =9/SinB.. That proportion would give me 87.5 derees.. However, the back of my book and.. http://www.trig.ionichost.com/ Says that B is 93.3 degrees.. However, if I were to approach the problem by solving for A (smallest angle) instead of immediately to B (mid sized).. I would get 41.7 degrees.. Then I could do B=180-A-C..or 93.3 degrees.. But still, if I set up a ratio of sin41.7degs/6=sinB/9, that's not 93.3, or 87.5, but 86.2 I'd like to know why math is stupid. And next time, what I should do to know whether 93.3, 87.5, or 86.2 would be the right answer.