If you take a sheet of paper and mark it with a diagonal line, as in
Figure A, you will find that when you roll it into cylindrical form, with
the line outside, it will appear as in Figure B.
[Illustration]
It will be seen that the spiral (in one complete turn) is merely the
hypotenuse of a right-angled triangle, of which the length and width of
the paper are the other two sides. In the puzzle given, the lengths of
the two sides of the triangle are 40 ft. (one-fifth of 200 ft.) and 16
ft. 8 in. Therefore the hypotenuse is 43 ft. 4 in. The length of the
garland is therefore five times as long--216 ft. 8 in. A curious feature
of the puzzle is the fact that with the dimensions given the result is
exactly the sum of the height and the circumference.