In the xy coordinate plane, a circle with radius 2 has its center at the point (3,5). When the circle is reflected across the x- axis its image is another circle. What is the distance between the centers of the two circle?

A) 4
B) 6
C) 8
D) 10
E) 14

The only thing that matters here is the centers—the circles themselves don’t matter at all! What’s the reflection of (3, 5) across the x-axis? (3, –5). What’s the distance between (3, 5) and (3, –5)? 10.