Question 957775
d is a maximum when yxz is linear and y and z are on opposite sides of x.
(x is the origin (0,0), y is (0,20), and z is (0,-12))
Then d=32 miles.
dis a minimum when z is directly between x and y
(x is at the origin, y is at (0,20) and z is at (0,12))
Then d=8 miles.
z can also rotate in an 8 mile radius from x (off the x axis) and give all values
between. 
So the range is 8 miles<=d<=32 miles.