Question

The sum of the measures of the interior angles of a convex polygon is 3060º. How many sides does the polygon have?

A. 17
B. 15
C. 19
D. 18

Answer 1

The formula for the sum of the measures of a polygon's interior angles is 180(n-2), where n is the number of sides.
3060 = 180(n-2)
17=n-2
19=n
Therefore, the polygon has C. 19 sides.

Answer 2

Use the formula:

(sum of interior angles / 180) - 2 = # of sides

(3060 / 180) + 2 = 19