The distance $d$ of a point $P$ to the line through points A and $B$ is the length of the component of $\frac{?}{\text{b}\text{a}\text{r}}(AP)$ that is orthogonal to $\frac{?}{\text{b}\text{a}\text{r}}(AB),$ as indicated in the diagram.

So the distance from $P=(4,-2,4)$ to the line through the points $A=(-1,3,4)$ and $B=(-4,5,-5)$ is