00:01
All right, so this problem has a, is even though it's in the law of cosine section, it's still a law of signs problem.
00:07
This is how i write my law of signs.
00:10
You might have the book that flips it, and it doesn't matter because they're just reciprocals.
00:16
So we don't know side length a.
00:18
We don't know side length c.
00:20
But angle c should be easy to figure out because the three angle measures need to add up to be 180.
00:27
So if you just do 180 minus 77 minus 42 with your calculator, you'll figure out that this angle must be 61 degrees.
00:36
I guess now is a good time to mention that you should be in degree mode with your calculator before trying to do this problem.
00:45
But from this point, all you need to do is cross multiply and divide.
00:53
So basically what it boils down to is if you're trying to solve for a, you're going to cross...