Originally Posted by NewYearsOld

If your finished squares will be 2" then here is the formula:

for the 1/2 sq triangles you will add finished(2) + 7/8" = 2 7/8" square cut in half diagonally.

for the 1/4 sq triangles you will add finished(2) + 1 1/4" = 3 1/4" square cut in half diagonally twice.