A 2 by X rectangle can obviously have 2*X circles of diameter 1 placed inside it without overlapping. What is the smallest integer X where a 2 by X box can have 2*X+1 non-overlapping circles placed inside it?

(In reply to Stumped by Steve Herman)

I've seen this problem before but haven't had time to solve it here.  Consider putting the first three circles as an equilateral triangle and the next three inverted.

Posted by Jer on 2017-05-23 07:32:14