Henry Ernest Dudeney/Puzzles and Curious Problems/191 - Two Squares in One/Solution
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Puzzles and Curious Problems by Henry Ernest Dudeney: $191$
- Two Squares in One
- Two squares of any relative size can be cut into $5$ pieces, in the manner shown below,
- that will fit together and form a larger square.
- But this involves cutting the smaller square.
- Can you show an easy method of doing it without in any way cutting the smaller square?
Solution
Place the two squares together so that $AB$ and $CD$ are straight lines.
Locate the centre point of the larger square.
Draw $AD$
Draw $EF$ and $GH$ through that centre point parallel to and perpendicular to $AD$ respectively.
Then you can cut out pieces $1$, $2$, $3$ and $4$, which, together with the smaller square $5$, fit together to form the big square of side $AD$.
Historical Note
This dissection was discovered by Henry Perigal in about $1830$, and published by him in $1873$.
Martin Gardner reports on it in detail in his $1966$ collection Martin Gardner's New Mathematical Diversions from Scientific American
Sources
- 1932: Henry Ernest Dudeney: Puzzles and Curious Problems ... (previous) ... (next): Solutions: $191$. -- Two Squares in One
- 1968: Henry Ernest Dudeney: 536 Puzzles & Curious Problems ... (previous) ... (next): Answers: $356$. Two Squares in One