If a regular polygon has exterior angles that measure 40 degrees each, how many sides does the polygon have?

A. 10

B. 9

C. 6

D. 8

The measure of the exterior angle of a regular polygon is the quotient when a whole revolution, 360 degrees, is divided by the number of sides (n). This is shown in the equation,

A = 360 / n

From the given above,

40 = 360 / n; n = 9

Therefore, the answer is letter B. 9.