Answer:
I think it would be 83.0448 or 83º
Explanation:
If X is the opposite of your hypotenuse then you would have to do inverse cos [a^2 +b^2 -c^2 all divided by 2ab]
so you would have the inverse cos of [8^2 +16^2 -17^2 divided by 2(8)(16)] which would give you 83º.
I hope this helped a little bit. Im sorry if it's wrong.