Originally Posted by
wantanaquilt
I came up with 3- 3 1/2 inch blocks which adds up to 10 1/2
You forgot to include the seam allowance. Three 3.5" blocks DO add up to 10.5", but when you sew them together, each seam eats up half an inch (a quarter inch for each patch). Once they're sewn, the final block (by itself) will measure 9.5". Once it's sewn into the quilt, it will measure 9".