Answer
$24 \sqrt{2}$
Work Step by Step
In order to simplify a radical, we consider the factors of the number inside of the radical. If any of these factors are perfect squares, meaning that their square root is a whole number, then we can simplify the radical. We know that 36 and 2 are factors of 72. We know that 36 is a perfect square, so we simplify:
$ 4\sqrt{36} \sqrt{2}=4*6\sqrt{2}=24 \sqrt{2}$
