The north displacement and the east displacement can be viewed as simply the legs of a right triangle and the distance between them is just the magnitude of the hypotenuse so:
h^2=x^2+y^2, where h is the distance between the two points, x is the easterly distance and y is the northerly distance....
h^2=.8^2+.6^2
h^2=.64+.36
h^2=1
h=1
So they are one mile apart from each other.
