Philip P. answered 04/15/19
Affordable, Experienced, and Patient Geometry Tutor
1, 2, 3, 4, 5 are the parts. The whole is 1+2+3+4+5 = 15. So the largest exterior angle is (largest part)/(whole) = 5/15 = 1/3 of the sum of the exterior angles. In a polygon, the exterior angles always sum to 360°, so the largest exterior angle is (1/3)(360°) = 120°.