Answer :
.

Here is a general
formula for solving this
problem. Call the two sides of the rectangle *a*
and *b*.

Then
( *a* + *b* - (*a*^{2} + *b*^{2} - *ab*)^{½}
)/_{6}

equals the side of
the little square pieces to cut
away.

The measurements given were 8 ft. by 3 ft., and the above rule gives 8
in. as the side of the square pieces that have to be cut away. Of
course it will not always come out exact, as in this case (on account
of that square root), but you can get as near as you like with decimals.