Answer
$d = 4.58$
Work Step by Step
$P_1 = (0,0,0)$
$P_2 = (1,2,4)$
We can find the distance between these two points:
$d = \sqrt{(x_2-x_1)^2+(y_2-y_1)^2+(z_2-z_1)^2}$
$d = \sqrt{(1-0)^2+(2-0)^2+(4-0)^2}$
$d = \sqrt{(1)^2+(2)^2+(4)^2}$
$d = \sqrt{1+4+16}$
$d = \sqrt{21}$
$d = 4.58$