Okay. So, I just worked out this problem with trial and error. I also think that my answer is correct. There are 12 sides in the polygon, and if it is a regular figure, it is 360*/12. So, you have (7x + 3)*. You know that 7x5=35, so 7x50=350. 350+3=353. That isn't at 360 yet. So if you multiply 51x7, you get 357, and 357+3=360. Your answer is x=51.
