The sum of all but one of the interior angles of a convex polygon equals 2570°. The remaining angle is:
- 90°
- 105°
- 120°
- 130°
- 144°
The sum of the interior angles of an n-gon is (n – 2)180°. We see that:
2570° = 14(180°) + 50° = 15(180°) – 130°.
Therefore, the missing angle in the 17-gon must be 130°. The answer is (d).