Answer
$w\approx4.36$ m
$l\approx 17.44$ m
Work Step by Step
$$l=4w$$
$$h=5$$
$$V=lwh$$
$$380=4w(w)5$$
$$380=20w^2$$
$$w^2=19$$
$$w=\pm\sqrt{19}\approx 4.36$$
Take the positive value:
$$w\approx 4.36\text{ m}$$
$$l=4w=4\sqrt{19}\approx 17.44\text{ m.}$$
