the length would still be the same 7"- the width of the strips is where your difference is going to be. you will have to cut some strips and add to strips you have to come up to the 2.25, or add an extra strip to the block- make it more scrappy- you could take your 1.5" strips, cut them at your 7", sew them together- line up the center seam with your ruler & trim to the right size- or, just make the blocks (strips wider than the pattern- or narrower)