The following link explains how to find distances between a point and a plane: http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/part-b-matrices-and-systems-of-equations/session-12-equations-of-planes-ii/MIT18_02SC_notes_6.pdf

However, there is a part of the explanation which I can not follow. If someone could go through the explanation starting from "using the relation" in example 2 with me I would be very grateful.

Question

The following link explains how to find distances between a point and a plane: http://ocw.mit.edu/courses/mathematics/18-02sc-multivariable-calculus-fall-2010/part-b-matrices-and-systems-of-equations/session-12-equations-of-planes-ii/MIT18_02SC_notes_6.pdf

However, there is a part of the explanation which I can not follow. If someone could go through the explanation starting from "using the relation" in example 2 with me I would be very grateful.

anonymous · Answer

Relevant part

anonymous · Answer

more specifically my question is, why do we reverse PQ to QP

anonymous · Answer

It shouldn't matter... |PQ| = |QP|.