 In number 14, we are going to just continue to use the same process we've used for the other problems. See that angle A is at the top, 8 is the adjacent leg, and 17 is the hypotenuse. So I'm going to set up cosine of angle A equals adjacent, which is 8, over hypotenuse, which is 17. So to solve for angle A, we're going to use the inverse cosine of 8 over 17. So we should get angle A is about 61.9 degrees. In number 15, angle A is this bottom left angle, and we are given opposite, 3 is opposite of angle A, and the hypotenuse. So we have sine of angle A equals opposite, which is 3, over hypotenuse, which is 3 root 2. Again, if you wanted to simplify this, sine of A equals 1 over root 2, and we have talked about in the past that you don't really want to have a square root on the bottom of your fraction, so this would equal root 2 over 2. And if I just step back for a second and I think about this fraction right here, 1 over root 2, and I think about the special right triangles we've learned about, remember that a 4590 triangle is x, x, and x root 2. So if you really think about it, if you have 1 over root 2, it means that you're really dealing with a 4590 triangle, because if you make this a 1, then this is root 2. And so if we have the fraction or the ratio 1 over root 2, that's opposite over hypotenuse. That's sine, what we're dealing with. So what angle measure is this? A 45 degree angle. Now you get the same answer if you plug this into your calculator. If you do inverse sine of 1 divided by root 2, you would get 45 degrees. In number 16, angle A is at the top, so we are dealing with tangent, because we are given opposite, which is 40, over adjacent, which is 9. So if we plug this into our calculator, inverse tan of 40 divided by 9, we get the measure of angle A is about 77.3 degrees.