536 Puzzles and Curious Problems

Paper Folding Puzzles 129

365. STRIP TO PENTAGON

Given a ribbon of paper, as in the illustration, of any length-say more than
four times as long as broad-it can all be folded into a perfect pentagon, with

B c

J I

every part lying within the boundaries of the figure. The only condition is that
the angle ABC must be the correct angle of two contiguous sides of a regular
pentagon. How are you to fold it?

366. A CREASE PROBLEM

Fold a page, so that the bottom outside corner touches the inside edge and

the crease is the shortest possible. That is about as simple a question as we

2

~ __ -:7:C

3>

· · •

· ·

..............

could put, but it will puzzle a good many readers to discover just where

to make that fold. I give two examples of folding. It will be seen that the crease

AB is considerably longer than CD, but the latter is not the shortest possible.