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Coin through a hole (Posted on 2006-05-29) Difficulty: 2 of 5
Take a piece of paper and cut out a perfect circle with diameter 1 inch.

What is the diameter of the largest unaltered coin which may be passed through the hole without tearing it?

(Consider the coin to be very thin, and the paper to be very flexible and tear resistant, but not at all stretchy.)

See The Solution Submitted by Jer    
Rating: 3.0000 (5 votes)

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My guess | Comment 10 of 24 |
I tried Charlie's paper folding trick to break the 180 degree arc into 2 segments, and experimentally measured the linear opening at about 1.4.
Next I did 2 more of these folds to split the 90 degree arcs in two parts.  This measured over 1.5 but not quite 1.6

So I think the theoretical limit is Pi/2  (Pi times the radius)

  Posted by Larry on 2006-05-30 01:08:07
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