Question

State 6✓216 is a surd?

Answer 1

this an also be written as 6 times(root 36 multiply by root 6)
which gives 6x6xroot 6
finally,it can be expressed as 36root 6

Answer 2

$6\sqrt{216}$
$= \sqrt{36}* \sqrt{216}$
$= \sqrt{216*36}$
$= \sqrt{6^{3}*6^{2}}$
$= \sqrt{6^{3+2}}$
$= \sqrt{6^{5}}$
$= \sqrt{7776}$
$= 88.18163...................$

So, I think that $6\sqrt{216}$ is a surd. 

Hope this may help you.