Ooow - much to early to wrap my brain around the math - I admire those of you who have given possible solutions. You came up with things I didn't even think to consider.

I have subscribed to this thread to see where it goes.

I'm enjoying watching this play out (sorry, I'm a bit warped). You all are going through various mental gymnastics that I did. A couple have come up with the solution. Somehow, we go through the hardest steps first, when actually it isn't that hard. It's good to know others take the hard path first. After a few days, I'll post the solution. I'm having too much fun to do it sooner. (Best solution a friend came up with was to either use a zipper or buy a new pillow form.)

A down & dirty way to do it: 15 & 19 can be divided by 3 (I know it is 18, just bear with me), so reduce 19 by 3, 15 by 3 and you get 16 & 12. But you want 15 for the long side, so 16-1=15, 12-1=11. Now you have 15 by 11, which isn't mathematically correct bu close enough for me.

I KNOW, but not telling.

Sorry, but you really haven't given enough information for anyone to come up with THE solution.

Why the suspense if you already know your own answer?

I think I understand, but is seems far too easy. Waiting for the answer to be posted. Then we will all say, "Well sure!" :)

This is for fun.

I think I'll ease all your minds....tomorrow.

Not funny...reading all the formulas given, made my brain tired....for a pillow! I would just cut the 19" side back to 15"...that's what she wanted isnt it! Now she has a 15" square pillow!