# What is 4 square root of 80?

$4 \sqrt{80} = 16 \sqrt{5}$
Simplify/solve it by finding factors of $80$ that are perfect squares and can be moved out of the radical sign.
$4 \sqrt{80} = 4 \sqrt{16 \cdot 5} = 4 \sqrt{16} \sqrt{5} = 4 \cdot 4 \sqrt{5} = 16 \sqrt{5}$