Geometry

Question Analysis:
This question requires multiple steps:
First, find the number of sides from the interior angle sum, then find the exterior angle.
The main focus is on using formulas for interior and exterior angle sums together.

Key Concept Explanation:
Sum of interior angles = (n – 2) × 180°
Exterior angle of regular polygon = 360° ÷ n

Step-by-Step Solution:
(n – 2) × 180 = 1260 → n – 2 = 7 → n = 9
Exterior angle = 360° ÷ 9 = 40°

Common Mistakes:
Using wrong formula: forgett...