Answer
$\sqrt{3}$
Work Step by Step
Formula to find the distance between two points is
$|PQ|=\sqrt{(x-x_0)^2+(y-y_0)^2+(z-z_0)^2}$
Let us consider $P=(3,4,5)$ and $Q=(2,3,4)$
Now,
$|PQ|=\sqrt{(2-3)^2+(3-4)^2+(4-5)^2}=\sqrt{(-1)^2+(-1)^2+(1)^2}$
or, $|PQ|=\sqrt {1+1+1}=\sqrt{3}$
