Oh, this looks like a pythag problem, to better understand pythag go to:
https://en.wikipedia.org/wiki/Pythagorean_theorem
So, we have Belmont 7 miles north, and Newton 6 miles east:
So, our a is 7 and our b is 6
We have to fit the formula:
a^2 + b^2 = c^2
49 + 36 = c^2
85 = c^2
so the square root of 85 is
approximately 9.2