00:01
There's a few options for you on how to get all of the angles, but you definitely need to start with the law of cosines.
00:11
And what's super important, and what i tell students, is to start with the largest angle, and in this case, has to be angle c because it's across from the largest side, 18.
00:23
Angle a is the smallest, it's across from 10, and then, oh, it's not even in centimeters, i just did a problem with centimeters on there, so.
00:33
And then b is across from 12.
00:36
So what i would do is find the measure of angle c first, which is the inverse cosine.
00:43
And what's important is that you do the two adjacent sides are the ones that are these numbers, and then you subtract off the one that's across from it over two times that two adjacent sides.
00:56
And make sure that you're in degree mode.
01:01
Maybe one more thing to point out is the law of cosines is used to, if you have three side links given to you, and it will also find the obtuse angle.
01:15
So as i type this, i get 1049, or sorry, 109 .4 because it doesn't tell me word around it, too.
01:22
So i'm going to go ahead and around to the nearest thousandths, 471 degrees...