For this you will need four pennies. Arrange the pennies so that the centers of all four are equidistant from each other.
(1) (2) (3) (4)
This will not work because penny 1 and penny 4 are farther apart than penny 1 and penny 2.
If we take a 3-D pyramid, the centres of the pennies at the base will be equidistant (equilateral triangle).
Also, the penny at the top will also be equidistant from each of the 3 other pennies(each of the sides will form an equilateral triangle).
Posted by Sparsh
on 2006-05-03 09:26:27