Distance between two points P(x1, y1, z1) and Q(x2, y2, z2) is given by
The co-ordinates of the point R which divides the join of A(x1, y1, z1) and B(x2, y2, z2)in the ratio m:n are:
When m = n, we find the co-ordinates of the mid-point of PQ as:
The co-ordinates of any points on the line joining two points
P(x1, y1, z1) and P(x2, y2, z2) are:
Where k ≠ −1
If k takes only positive real values, we get the co-ordinates of the points on the Segment PQ (except P and Q).