I think #3 is likely 2 3/4" strips. But that's based on math, not practice, as I don't have an omnigrid ruler. The math I used - for a 3" finished triangle, the finished distance from center to point of one triangle is 3/4 of the finished size - so 2 1/4". Then add seam allowances on each side of the strip, and you need two 2 3/4" strips.