Select the correct answer. An exterior angle of a regular convex polygon is \( 40^{\circ} \). What is the number of sides of the polygon? A. 8 B. 9 C. 10 D. 11

To find the number of sides \( n \) of the polygon, we can use the formula for the measure of an exterior angle of a regular polygon, which is given by: \[ \text{Exterior Angle} = \frac{360^{\circ}}{n} \] Given that the exterior angle is \( 40^{\circ} \), we can set up the equation: \[ 40 = \frac{360}{n} \] By rearranging, we get: \[ n = \frac{360}{40} = 9 \] So, the correct answer is **B. 9**. To elaborate a bit further, if you ever find yourself working with polygons, just remember that the sum of the exterior angles always equals \( 360^{\circ} \). Each exterior angle gives you a sneak peek into the shape of the polygon, turning it into an angle puzzle where the pieces need to fit perfectly! It's like building a Lego model – each piece has its place so you can achieve that perfect finished shape.