I am trying to make my MIL a quilt for her bed, and I have some Christian panels to also use in the quilt top. The rest of the top I would like it to be a D9P.. The panels are 16.50 x 16.50. Would I make each small square 5.75? That would be 5.75 x 3 = 17.25 - 2 seam allowances for the first sewing = 16.75. Then minus another seam allowance for the second sewing = 16.50 Did I do the math right? Some day, I hope to get as good as all you sweet people on this board. Until then..I am enjoying my journey along the path.

I'm math challenged too so I can't help but I wanted to know did you make that quilt in your avatar? It's beautiful!

I think 6" squares will give you the finished size you want. Try it with paper first so you don't waste fabric.

Yes I did make the quilt in my avatar.. well a UFO right now. Ha ha ha...add to my list of them.

I don't know the answer to your question. When math comes up, my mind just wanders to a "happy place", I get a glazed look on my face and all I hear is "Whaaaa Whaaaaa Whaaaa"!

Yep, this is what I got, too.

I assumed the finished size of the panel and thus of the D9P block is 16'', isn't it? In that case 6'' squares to start with is the correct size.

Sketch it on (graph) paper so you have a visual. Then figure the basic elements. Climb that mountain with the first step.

A 16.5 panel will finish to 16 inches on a side. that means that the finished size of whatever goes next to it also has to be 16 inches. So four 4 inch blocks (raw size 4.5)works. In order to put three blocks on a side they have to finish at 5.33 inches, so add half inch to that finished size for seam allowances and they have to be 5.33 + .5 or 5.83 raw. I can't cut that measurement, can you? Your plan for 5.75 inch blocks will be slightly short. Any multiple of 4 will work, like two 8 inch blocks, but then you are going to try to divide the 8 inch measurement by 3 if you really plan to use D9P blocks, and again, you will have a hard time getting it to work. You could put a small, plain border around the panel to get it to a number easily divisible by 3, like a 1 inch border (1.5 raw) which increases the panel to 18 inches and now you can work with the D9P design. Clear?

Sorry to object, but for a D9P she can easily start with nine 6'' squares, resulting in a 17'' 9patch, cut and sewn together again resulting in a 16''1/2 D9P.

I've tried to make a sketch but my math is better than my explaining.

I respectfully disagree with Thusnelda. Six inch blocks finish to 5.5. So the middle square on the D9P will be 5.5. The top and bottom squares will only use ONE seam allowance each at this point(where they are sewn to the middle square) so at this stage they will be 5.75 inches. So now you have 5.5 inches plus 5.75 plus 5.75 which totals 17 inches. Too long for her panel. She needs to put a border around her panel in order for it to accept these D9P blocks. In Thusnelda's math above, 18" minus 4 seams at .25 each DOES equal 16.5 but this does not account for the top and bottom seam allowances of the D9P, only the four seam allowances used to sew the top and bottom rows together. So the D9P at this stage will be 17 inches.