Largest sphere in the space between dense packed spheres

[iantresman]

If I consider a tetrahedron of four densely packed spheres of unit radius, what it the radius of the largest sized sphere that can fit in the space in between?

 

[BvU]

Well, since this is PF, the inevitable reply is: what did you do so far to find it ?
Did you alredy draw the tetrahedron in the usual manner (lines) ?

 

[iantresman]

I didn't know where to start, whether drawing a tetrahedron and 2D circles is relevant.

 

[BvU]

If you have a better idea, follow that !

 

[fresh_42]

Thread closed, as it is a homework type question.

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