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°.
Krystal S.
asked 04/15/19Exterior angles on Pentagon
the measures of the exterior angles of a pentagon are in a ratio of 1:2:3:4:5. The measure of the largest exterior angle is?.
2 Answers By Expert Tutors

Mark H. answered 04/15/19
Mathematician with 20+ years of Tutoring Experience
I am going to assume that the interior angles of a pentagon has the same ratio as stated in the problem.
I can sub-divide a pentagon into 3 triangles which tells me that the total amount of degrees in a pentagon is 540. I can model the ratio of the interior angles as x + 2x + 3x + 4x + 5x = 540 -------> 15x = 540 ----> x = 36 which is the smallest interior angle. The largest interior angle is 5x = 5(36) = 180. The largest exterior angle would be 360 - 180 = 180 degrees.
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