DELTA_PROBEABLE_RADIUS

Hello, I new to all this, so please be patient.
I'm trying to configure Marlin RC7. When I try to verify, I get this message in Marlin_main.cpp: exit status 1 'DELTA_PROBEABLE_RADIUS' was not declared in this scope.
The actual line in the Marlin_main.cpp is: DELTA_PROBEABLE_RADIUS / 8, DELTA_PROBEABLE_RADIUS /3

I have no idea what the numbers 8 and 3 refer to and how I would determine what numbers should go there. Someone, please school me! Thank you!

I also have this problem when I did it, and I fix the problem

=====at Bed auto leveling setting====, you can see that there is a "#define DELTA_PROBEABLE_RADIUS (DELTA_PRINTABLE_RADIUS - 10)",
this is set the DELTA_PROBEABLE_RADIUS, but this is not gonna work.

Above this line, at the top of =====Bed auto leveling setting=====,
you can find a " //#define AUTO_BED_LEVELING_FEATURE // Delete the comment to enable (remove // at the start of the line)"

So what you should do is to Delete the comment.