The slope (or angle) of the toolpath is independent of the tool nose radius.
The nose radius will effect the size of a chamfer or corner break.
Anyway, to calculate the angle:
angle = arctangent(rise / run)
= arctangent (change in X / change in Z)
= arctangent( ((1.025 - .875)/2) / (-.593 - -.518) )
x is diameter value, divide by 2 for radial distance
= arctangent (-1)
= -45 degrees