Law of Sines Proof

1. Aug 1, 2009

razored

1. The problem statement, all variables and given/known data
Prove the law of sines using a vector cross product. (Hint, consider the area of the triangle and that A+B+C=0.)

2. Relevant equations
|A||C|sin ( θ ) = (a2c3 − a3c2) + (a3c1 − a1c3) + (a1c2 − a2c1)

3. The attempt at a solution
The farthest I went is to show .5 |a||c|sin \theta .. i've tried some other things but then it just turns out to be some incomprehensible mess. I chose C to be my longest side. I simply do not know what to do; i've exhausted both forms of the cross product I know, and it appers to go nowhere.

2. Aug 1, 2009

razored

Never mind, I figured it out. Thanks anyway!