Understanding Coplanar Parallelepiped in Vector Algebra

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I have just completed a question in which I have determined:

(axb).c = 0 = det [a,b,c]

Where: a = (1,1,2) b = (2,3,4) c = (1,-2,2)


With some googling, I established this meant the parallelepiped to be coplanar but I'm not sure exactly what this means. If anyone could offer me some assistance with this I would be most grateful.


Cicatriz
 
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It means that all of the edges of your parallelepiped lie in the same plane. So the box is squashed flat and has no volume.
 
Dick said:
It means that all of the edges of your parallelepiped lie in the same plane. So the box is squashed flat and has no volume.

Thanks!
 
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