I am have one of my senior moments and can't seem to figure this out. I have nine patch 3.5 inch squares that I want to set on point...what size should my setting triangles be?

I seem to be having a senior moment too. Not sure what size block you are wanting setting triangles for. So here's a link to Bonnie Hunter's instructions for cutting side and corner setting triangles. You can use it to determine the size of triangles you need based on the finished size of your nine-patches.
http://www.stcroixquilters.com...ting%20triangles.htm

Thanks, math is a big black hole to me!!
I used the formula and came up with a 6.25 in square cut diagonally twice. I will see it that is close.

Thanks for the Bonnie Hunter site. I have put it in my Bookmarks - so I can have it when I finish the quilt I am working on. Once again you guys are a lifesaver!