Well, it's been well over 50 years since my high school geometry classes, so maybe some of you whizzes can solve a minor problem for me.

I'm trying to make a game board that requires it to be an equilateral octagon. I'm starting with a 2' x 2' hunk of plywood. My first instinct was to mark down each side eight inches and the 16 inches, then connect the corner marks. Well, that doesn't work out. The cut side becomes much longer than the eight inches of the uncut side, and symmetry is lost.

So how do I measure that board to turn it in to an octagon equal on all sides?