another way is to pin or baste the ends, then proceed slowly around the arc, lining it up as you go. you might need to stop every inch or so, lift the foot and re-align things.
you will need to stretch it juuuusssst a leeeeeetle bit to match up the top of the arch with the inner curve of the center.
when i used this method, i added a pin to the center when i was about two inches away. just to reassure myself. in the end, i found it wasn't totally necessary.