If the sum of the interior angles of a polygon is 900°, then how many sides does the polygon have?

A. 6 sides
B. 7 sides
C. 5 sides
D. 9 sides

We can use the formula for the sum of the interior angles of a polygon, which is (n-2) x 180 degrees, where n is the number of sides in the polygon.

Given that the sum of the interior angles is 900°, we can set up the equation:

(n-2) x 180 = 900

Simplifying this equation, we get:

n - 2 = 5

n = 7

Therefore, the polygon has 7 sides, and the answer is B.