I purchased a "circle cutter" ruler, one in which you put the folded piece of fabric on a line and then with a rotary wheel (small - 28 mm) cut out the circle.
I have tried this on a bunch of scraps, and can't for the life of me figure out a way to do this easily. I wonder if anyone out there in "quilter world" has done this, and is there an easier way?
This ruler was pretty expensive and since I've already used it, I can't return it. I want to cut out a bunch of circles about 6-7 inches diameter for a quilt, and using this method is incredibly laborious.
Thanks to everyone for all your good ideas.