Apply a Fillet to a Circle

If one puts a partition inside a circle for two separate areas for area clear is it possible to put a fillet on the end of the partition that touches the circle with the fillet tool
I was going to us a 1/4 end mill but wanted a 1/2" fillet. I can do it with a circle and the snip tool , but just curious if the fillet tool is for square corners only? I can only get it to work on square corners

Would be good if you told us what software you are using.

Sorry, that would help, carveco maker