Originally Posted by Moonpi

When I use templates for angular shapes, I just tape them to the ruler. If the seam allowance needs to be added, I figure that in also. For that particular pattern, I'd make the middle four patches and square them up. From that measurement, I'd add an inch, and make half square triangles, which I would cut on the diagonal to get my corners. That should leave a tiny bit of wiggle room to do the final squaring up.