How do you find angles in pentagon which is in a circle, when you are only given two angles.?

The pentagon which is in the cirlcle has two angles which are known, one is 50 degrees the other is 80 degrees, you are asked to find the other three angles. I know that in a quadilateral and tzium all angles add up to 360 degrees and in a trainlge they add up to 180 degrees so what about a pentagon?