Hello, Josh!
You're expected to know the Distance Formula . . .
Given points P(x<sub>1</sub>,y<sub>1</sub>) and Q(x<sub>2</sub>,y<sub>2</sub>),
. . . . . . . . . . . . . . . . ._________________
. . distance PQ . = . √(x<sub>2</sub> - x<sub>1</sub>)<sup>2</sup> + (y<sub>2</sub> - y<sub>1</sub>)<sup>2</sup>
The distance between the points (3, 4) and (-9, 9) is:
. . . . . . . . _______________
. . d . = . √(-9 - 3)<sup>2</sup> + (9 - 4)<sup>2</sup>
. . . . . . . . __________
. . . . .= . √(-12)<sup>2</sup> + (5)<sup>2</sup>
. . . . . . . . ._______ . . . . ___
. . . . .= . √144 + 25 . = . √169 . = . 13
