Henry Ernest Dudeney/Modern Puzzles/129 - The Circle and Discs

by : $129$

 * The Circle and Discss
 * During a recent visit to a fair we saw a man with a table,
 * on the oilcloth covering of which was painted a large red circle,
 * and he invited the public to cover this circle entirely with five tin discs which he provided,
 * and offered a substantial prize to anyone who was successful.
 * The circular discs were all of the same size, and each, of course, smaller than the red circle.
 * he showed that it was "quite easy when you know how," by covering up the circle himself without any apparent difficulty,
 * but many tried over and over again and failed every time.
 * It was a condition that when once you had placed any disc you were not allowed to shift it,
 * otherwise, by sliding them about after they had been placed, it might be tolerably easy to do.


 * Let us assume that the red disc is six units in diameter.
 * Now, what is the smallest possible diameter for the five discs in order to make a solution possible?