Doesn't really make sense actually. Type of i3 is quite general. There are 5 generations and dozens of models available. Really depends on what type of motherboard you have.
Are you trying to add an R7-260X to an existing i3 system? Have a system with some other CPU that you want to add the r7-260X to? Or, want to upgrade the CPU in a system that already has an R7-260X?