when do you use the law of cosines and the law of sines?

Question

imstuck · Answer

The law of Sines requires either 2 angles to be known and one of the angle's corresponding sides, or 2 angles to be known along with one of its corresponding angles.  For example if you know the measure of angle A and you have side a and angle B, you can solve for side b.  Vice versa with solving for angles.  The Law of Cosines is a bit more work.  In order to solve for a missing side, you need the lengths of both the other sides and the value of the angle that corresponds to the side for which you are solving.  For example in order to find the length of side a, you need to know sides b and c and the value of angle A.  If you need help with specific problems, let me know!

anonymous · Answer

Thanks for the help!