Final answer:
To determine the number of sides of a polygon where each interior angle is 120°, you can use the formula for the sum of interior angles of a polygon ((n - 2) × 180° = n × interior angle). By solving for n, you find that the polygon must have 6 sides.
Step-by-step explanation:
To find out how many sides a polygon has based on the measure of its interior angles, we use the formula:
(n - 2) × 180° = n × interior angle, where n is the number of sides of the polygon.
If each interior angle measures 120°, we can set up the equation
(n - 2) × 180° = n × 120°.
Solving for n:
- 180n - 360 = 120n
- (180n - 120n) = 360
- 60n = 360
- n = 360 / 60
- n = 6
Therefore, a polygon with interior angles of 120° must have 6 sides, making it a hexagon.