I need to make 20 squares made from two triangles. The finished square is to be 1 5/8 inches by 1 5/8 inches. I would like to make it the fast way using two squares that are sewn together and then cut apart. My problem is trying to figure out what size the squares that I cut apart should be. Most charts don't go that small . I hear you just muiltiply by .64 but how do you do that with a number like 1 5/8?? Can any math whiz help me??