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nydus/The Canterbury Puzzles, and Other Curious ProblemsPublic

Henry Ernest Dudeney collects a wide variety of original mathematical and mental puzzles into this volume. The book features an introductory essay on the nature of puzzles and provides solutions for all problems at the end.

Page 50 of 307
Table of Contents

28 .— The Great Dispute between the Friar and the Sompnour.

portions of this path measures exactly 25 yards. Similarly in Fig. 2, the zigzag contains ten straight portions, each 20 yards long: that path is also the same length—200 yards. No matter how many steps we make in our zigzag path, the result is most certainly always the same. Thus, in Fig. 3 the steps are very small, yet the distance must be 200 yards; as is also the case in Fig. 4, and would yet be if we needed a microscope to detect the steps. In this way, the Friar argued, we may go on straightening out that zigzag path until we ultimately reach a perfectly straight line, and it therefore follows that the diagonal of a square is of exactly the same length as two of the sides.

Four diagrams show a square with a total length and height of 100 yards, demonstrating that a stepped diagonal remains 200 yards long regardless of the number of steps.

Now, in the face of it, this must be wrong; and it is in fact absurdly so, as we can at once prove by actual measurement if we have any doubt. Yet the Sompnour could not for the life of him point out the fallacy, and so upset the Friar's reasoning. It was this that so exasperated him, and consequently, like many of us to-day when we get entangled in an argument, he utterly lost his temper and resorted to abuse. In fact, if some of the other pilgrims had not interposed the two would have undoubtedly come to blows. The reader will perhaps at once see the flaw in the Friar's argument.

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