# What is the distance between (5, 6, 4)  and (2, –3, 1) ?

= $\sqrt{99}$
$d = \sqrt{{\left(\text{diff of x's")²+("diff of y's")²+("diff of z's}\right)}^{2}}$
$d = {\left(9 + 81 + 9\right)}^{0.5}$
$d = \sqrt{99}$