yes, that's five sides. then with your protractor, you will know the name of the polygon itself. because it's the whole circle, 360, after that, divide it by the angle. like, 360 ÷ 6 = 60. then with your protractor, from 0 to 60, there are the sides or angle non. just like that
The rationale is that 360 is "highly divisible". When all you have to work with are integers you tend to divide things up into a number that you can make fractions of very easily. 360 gives a good amount of accuracy with divisibility.