Henry Ernest Dudeney/Puzzles and Curious Problems/329 - The Four Pennies

by : $329$

 * The Four Pennies
 * Take four pennies and arrange them on the table without the assistance of another coin or any means of measurement,
 * so that when a fifth penny is produced it may be placed in exact contact with each of the four (without moving them)
 * in the manner shown in the diagram.
 * The shaded circle represents the fifth penny.


 * Dudeney-Puzzles-and-Curious-Problems-329.png


 * How should you proceed?

Also see

 * by : $213$ - The Six Pennies