• Re: 153. - A CUTTING OUT PUZZLE

    From Charlie Roberts@croberts@gmail.com to rec.puzzles on Mon Sep 29 13:04:39 2025
    From Newsgroup: rec.puzzles

    On Sun, 28 Sep 2025 10:46:56 +0100, David Entwistle <qnivq.ragjvfgyr@ogvagrearg.pbz> wrote:



    Dudeney's solution says:

    The illustration[*] shows how to cut the four pieces and form with them
    a square. First find the side of the square (the mean proportional
    between the length and height of the rectangle), and the method is
    obvious. If our strip is exactly in the proportions 9 x 1, or 16 x 1, or
    25 x 1, we can clearly cut it in 3, 4, or 5 rectangular pieces
    respectively to form a square. Excluding these special cases, the
    general law is that for a strip in length more than n^2 times the
    breadth, and not more than (n + 1)^2 times the breadth, it may be cut in
    n+2 pieces to form a square, and there will be n - 1 rectangular pieces
    like piece 4 in the diagram. Thus, for example, with a strip 24 x 1, the >length is more than 16 and less than 25 times the breadth. Therefore it
    can be done in 6 pieces (n here being 4), 3 of which will be
    rectangular. In the case where n equals 1, the rectangle disappears and
    we get a solution in three pieces. Within these limits, of course, the
    sides need not be rational: the solution is purely geometrical.

    [*] An image of the solution is available on-line at the following links:

    http://puzzles.50webs.org/a153.html

    and

    https://archive.org/details/amusementsinmath00dude/page/172/mode/1up

    Amazing! Thanks for this general solutuion.

    As I said earlier, I am absolutely terrible at dissection puzzles.
    Always thought of them as one-off wonders. But, now, here
    is a general solution for this class of problems.

    I do not remember seeing anything like this solution in Martin
    Gardner's writings, but I could have missed it.

    One to salt away.

    Thanks.
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