To find the distance between a point (x,y,z) and a plane defined by Ax+By+Cz=D, one must first determine the normal vector (N) of the plane, which is given by the coefficients (A, B, C). The distance can then be calculated using the formula that involves the normal vector and the point's coordinates. A line perpendicular to the plane can be established by using the normal vector and the point in question. The equation N·P - D=0 can help in understanding the relationship between the point and the plane. This discussion highlights the importance of vector calculus concepts in solving geometric problems.