How to setup and gcode for a large arc?

The project is to create a number of parts with an arc. The blanks are 1 inch by 1/2 inch by 3 inches. The project is to mill a 10 inch diameter arc in the 1/2 inch side with the arc starting and ending in the corners.
In this example The distance from the arc center to the corner is 10 inches, the hypotenuse. The distance to the center, adjacent, is 9.8869 inches.
My plan is to mark the center of the blank on the half inch side and clamp it perpendicular to the X azis. Then home the mill on the center mark.
Now the 'direct' approach is to move X to -9.8869 and home X and Y. Now it is a simple to move to X to 9.8869 and Y to 1.5 and then mill the arc.
Is there a way to do this without actually having to move the bed back and actually setting home? Is there a 'relative' 0 function or offset?

In the top left corner of the axis gui, select your axis and then press the touch off button below it. You can then set your offset to zero or whatever number you want.

Good luck.

Thank you. That sets G54 to the negative offset value. What role does G54 have? Does it affect operation?

G54 is the coordinate system you are in unless you explicitly change into another one.

I print it out a hard copy of the manual and had it bound at a local print shop. I keep it by the machine and often refer to it when I have questions and there's a couple of blank pages in the back where I keep some notes about issues I keep running into.

It's pretty full of information and a lot of that information is dense so you can read it a few times before something like coordinate systems makes sense. I understand them, I sometimes use them but generally I need to go to the manual to sort things out when they get weird.