Answer
$2\sqrt{10}$
Work Step by Step
We find the distance between the second and fourth points, $(1,-3)$ and $(3,3)$ by using the distance formula:
$d=\sqrt{(x_1-x_2)^2+(y_1-y_2)^2)}$
$=\sqrt{(3-1)^{2}+(3-(-3))^{2}}$
$=\sqrt{2^{2}+6^{2}}$
$=\sqrt{4+36}$
$=\sqrt{40}$
$=\sqrt{4*10}$
$=2\sqrt{10}$