4½" is the correct size. Whenever I watch the Missouri Star Tutorial, I feel she hurries herself and says 4-1/4" instead of the 4-½" strip. I hope you haven't cut too many of them, yet. I will say that the Missouri Star Tute taught me how to use a regular ruler instead of buying a special ruler to cut the triangle squares. I have made over 40 tops using those squares trying to get the best use of my scraps.