Quote Originally Posted by Skouperd View Post
Nope still not... let me help you out again...

1. If you start your bottom layer with 10 x 10 then that gives you 100 ball bearings.
2. if you stack your second layer 9 x 9 (81 bearings) with each ball bearing sitting in the lowest point between the botton 4 ball bearings, the height of the second row will only be 1.541196 cm.
3. The third layer you again pack 10x10, but then that layer is 2.082392cm in height.
4. continue with this pattern, 100 then 81, then 100, then 81 until the container is full then you get at least 724 ball bearings in which is greater than the 707 you mentioned.
5. A word of advise, this ain't no simple puzzle and you need to apply some brain power to it as Google will not give you the correct answer.
If you stack the second layer as 9x9, you won't be using all of the available space, surely you'd have to take one sphere off both sides and pack 8x8 to be optimal?

How do you get the height of 1.541196cm given the 9x9 packing? I tried finding a method to work that out (without diving into all kinds of trig that I haven't touched since school) and went for an easier option instead.