To each side of the Earth. Because you said in the problem statement, that the satellites are 110 miles above the surface of the earth. That's 110 miles one ONE side, but because they circle the entire earth, you have to add 110 TWICE, to represent the distance of the satellites from both sides of the earth.
I'm gonna brake this down really basic. Draw a circle and think of it as the earth. Then draw another circle around it, bigger, and think of that as the circle of the satellite's orbit. To solve your problem, you need the circumfrence of the BIGGER circe, cuz that's the line the satellites are spaced out on.
To figure out the circumfrence of the bigger circle, you need to find the diameter of the bigger circle. Since you know the circumfrence of the smaller circle (the earth) you calculate to find IT'S diameter.
Draw a line straight down the middle of both circles. The diameter of the bigger circle is the earth's diameter plus the distance between the bigger circle and the smaller circle. You know that's 110 miles because your problem says so.
Get it yet?
its not much off os i probably messed up somewhere