If I have a square and want to place four equally large circles within this square, how large can the maximum radius be (compared to the lenght of the side of the square)?
Just an answer would be ok, but answer and explanation would be better.
If I have a square and want to place four equally large circles within this square, how large can the maximum radius be (compared to the lenght of the side of the square)? Just an answer would be ok, but answer and explanation would be better. 


See the links below. The solutions have been show to be optimal up to 20 circles into a square. http://mathworld.wolfram.com/CirclePacking.html A fun site about all kinds of packing results is: 


Here are some additional formulas/numbers about circle distances: http://en.wikipedia.org/wiki/Circle_packing_in_a_square 

