You are given six sticks of integral lengths 1, 2, 3, 4, 5 and 6. Using these sticks, can you make a tetrahedron (4sided, 3D figure, with a triangle on each side)?
If so, show how. If not, replace any one of the sticks with the smallest stick of integral length greater than 6 that allows you to build such a tetrahedron and show how it can be done.
(In reply to
re(2): Multiple ways (spoiler) by Steve Herman)
Do you need to check all spans, or only the longest?
I'm pretty sure you only need to check the longest.
To check whether 7 spans I put together the triangles that don't involve 7. These are the smaller triangles. To check whether 6 spans I'd put together the triangles that don't involve 6. But one or two of these will involve 7 and be larger triangles.
This might be a good perplexus problem in its own right...

Posted by Jer
on 20140130 15:54:33 