Answer:
it should be 30 or something I'm pretty sure that's the answer

Because (4*3) + 3 = 15. Similary find the improper fraction for -2 1/2.
(15/4) / (-5/2) = -3/2
Convert -3/2 into a mixed fraction.
Therefore, -3/2 = -1 1/2.
Exterior angle = 360/25 = 14.4 degrees
internal angle = 180-14.4 = 165.6 degrees
sum of all the angles = 165.6*25 = 4140 degrees answer