Just curious about a certain facet of the vector description of a plane. My query is as to why it is defined as n • (r-r0) = 0. Great, that's because any two vectors with a dot product of 0 must be orthogonal to each other and if we have a point on a infinite plane with an associated vector we can define the plane perfectly. BUT here is my problem (Which will be resolved after a few minutes on here, I'm sure) If we can define the vector (r-r0) as a single vector, say a, then why it seems to me that a multitude of different n vectors could be orthogonal to vector a, and thus it seems like a poor definition of a plane. Just wondering if anyone can clear this up for me. :) Thanks.