I may be wrong, I think I remember how to do this. A straight line has an angle of 180, so y would be 133, making the area 55571.63u. (u = whatever unit is measuring the circle.) If x = 1/20 of the area, then the red area = 2,778.5u or 2,779u. I hope this helps, but I honestly don't remember how I would find x, and I don't want you to get the question wrong.