Anne, I noticed that when I printed out the triangles that on 2 sides the seam allowance is NOT 1/4". One side is correct. I line my ruler up with the outer edge of the pattern line and trim to 1/4" rather than cutting on the line that is there. If you sew on that line I think you'll end up with the correct size but I'd rather have all my seam allowances cut to 1/4".
Yes, QE, while I appreciate the measurements given to cut the fabric, I'm afraid I'm stuck in my Hack & Whack ways. It's amazing how little wasted fabric there is; I put all the trimmings in an apothecary jar and use them up on small blocks. The only thing I measure is large elongated triangle shapes and I usually screw them up at least once. I also don't cut all my fabric pieces at once. I do it section by section in case I don't like the color combo once I see a completed section.