You need to use Right Angle Trig. to find your X,Z axis start and end points.
If you want just a 45 Deg cham and you have the option turned on in the contol, You can use the C word.
This will make a 45 Deg. Cham .100 wide.
Other degrees, say, 30 Deg. You must find the start point on the diameter X and the end point of Z. and just program like such:
X.750Z-.100 (30 DEG ANGLE)
Without the A word option, you must figure the start and end points for angles. Remember to use TNRC or your angles will be wrong. Use a right angle trig calculator or do it long hand. You can also get a pocket hand book for Right Angle Trig. Companies used to give these books out like Decimal equivilant charts. Not sure if they still do. Mine are from the 1950's and 1960's