I've made quite a few disappearing 9 patches but always with scrap fabric. Now my friend wants to purchase fabrics to make a longer lap type one. Maybe about 50"wide by about 80" long. It would be 3 colours, any idea how much fabric she would need of each colour?

figure out the size of your starting block and then determine how many 9 patches you have to make to reach the size quilt you want.

I made a twin size Twisted D9P from 3 fabrics including borders. I used 2 yards of each with very little left over. I think I started with 9" blocks. I'll attach a picture if it will let me.

Remember to subtract the seam allowances you use when making the D9P for the 9 patch.

Or easier yet ... make a 9 patch then cut it up for the D9P and you can figure out how many of that unfinished D9P you will need.

ali