The command Distance(p1, p2) computes the distance between the points p1 and p2, which must have the same dimensionality (and orientation, when each of the points is a Vector).

This command is part of the Student[Precalculus] package, so it can be used in the form Distance(..) only after executing the command with(Student[Precalculus]).  However, it can always be used in the form Student[Precalculus][Distance](..).

$\mathrm{with}\left(\mathrm{Student}:-\mathrm{Precalculus}\right)\:$

$\mathrm{Distance}\left(\left[0\,0\right]\,\left[1\,2\right]\right)$

$\sqrt{5}$

$\mathrm{Distance}\left(⟨1\,2\,3⟩\,\left[0\,-1\,2\right]\right)$

$\sqrt{11}$

$\mathrm{Distance}\left(⟨0\,0⟩\,⟨1\,2⟩\right)$

$\sqrt{5}$