The sum of the interior angles of a polygon is 1440°. How many sides does the polygon have?
Answer: C
The formula for the sum of the interior angles of an n-sided polygon is (n-2) × 180°.
(n-2) × 180° = 1440°
n - 2 = 1440 / 180
n - 2 = 8
n = 10.
The polygon has 10 sides (a decagon).