Verified Answer :

\(3\sqrt{216} \\ \\ 3 \times 6 \sqrt{6} \\ \\ 18 \sqrt{6} \\ \\ Answer: 18 \sqrt{6} \ or \ 44.0908\)

3 √216 = 18 √6

I first got simplified the square root of 216.
√216 = √4 54                
 > i used 4 because it can has a whole number, 2, as a square root

√216 = 2
 √54 = 2  √9 6
> i factorized 54 to look for a factor that has a whole number as a square root. the number is 9.

√216 = 2 3  √6
√216 = 6 √6

***

3 √216 = 3
6 √6
3 √216 = 18 √6