Question

What is the distance between `(–2, 1, 3)` and `(–2, 0, 1)`?

Answer 1

`sqrt(5)`

Explanation:

By plotting this out in stages and calculating the projected images on the x,y,z planes you end up with a 3 variable equivalent of the Pythagoras theorem

Let the distance between points be `d`

`=> d= sqrt( (x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2)`

`=>d =sqrt( [-2-(-2)]^2+[1-0]^2+[3-1]^2)`

`=>d=sqrt(0+1+4)`

`=>d=+-sqrt(5)`

But the negative side of `sqrt(5)` is not logical for this context so we are only interested in `+sqrt(5)`