You know how to do the first one.
For the second one, let's say that polygon has an
n number of sides. We know that the interior is 160. So you can recall your formula for getting the interior angle and apply it in terms of
n. Not sure how challenging you would find this because it involves some algebraic manipulation (I can walk you through it if you wish). Or alternatively, you can also find it because you know that the exterior angle of a regular polygon is found by
n360​ so you can solve for
n as you know what the exterior is. I believe this is the way they expect because it's shorter but either is valid.