[Leaning Right]

My best guess:

Assuming most of the pieces are non-standard,

A “yard” is 36 x 60 = 2160 (inches?)

So, if my math is right:

1/4 = 540
1/2 = 1080
2/3 = 1440
3/4 = 1620

And your 17 x 42 piece = 714.
714/2160 = 0.33 = 1/3 of a yard

[beergarden]

Wow, thanks.