An exterior angle of a regular polygon is one-third of its interior angle. How many sides does the polygon have?
Answer: B
Let the exterior angle be x. The interior angle is 3x.
The sum of an interior and its corresponding exterior angle is 180°.
x + 3x = 180°
4x = 180°
x = 45°.
The exterior angle is 45°. The number of sides n = 360° / 45° = 8.