If you did check out that link I posted earlier for making 1/2 triangle squares quickly, then you may be interested in knowing that if you start with;
4 1/2" squares you will get four 2 3/4" squares using that method
5".......................................four 3 1/4" squares
5 1/2"................................four 3 1/2" squares
6"......................................four 3 3/4" squares
6 1/2"................................four 4 1/4" squares
7"......................................four 4 1/2" squares
8"......................................four 5 1/4" squares
These were my measurements. To be sure that you get the same, you can always use scrap fabric to test it yourself. I had some fabric that I looked at while I was re-organizing a few months back and was like "Why in the world would I pay money for this?" So I used that to test the different measurements. Good luck!