This is just to confirm my idea on how to do this problem:
On a map, Cynthia lives $1$ mile east & $1.5$ miles south of a school. Charles lives $2$ miles west & $0.8$ miles south of the same school. How far apart (in miles) do they live from each other?
So I thought:
Cynthia lives $2.5$ miles from school. Charles lives $2.8$ miles from school.
But they are not driving to school. They are driving to each other. Therfore:
Cynthia lives $3$ miles from Charles.
This soultion was way too easy so I did not want to trust myself with this.
Could it perhaps be instead:
$1.5-0.8 = 0.7 => 3.7 \text{ miles}?$