[tex]\Large\boxed{\begin{array}{l}\begin{array}{c|c}\sf400&\sf2\\\sf200&\sf2\\\sf100&\sf2\\\sf50&\sf2\\\sf25&\sf5\\\sf5&\sf5\\\sf1\end{array}\\\sf \sqrt{400}=\sqrt{2^2\cdot2^2\cdot5^2}\\\sf \sqrt{400}=2\cdot2\cdot5\\\sf\sqrt{400}=20\checkmark\end{array}}[/tex]