Answer :

sqrt of 864 = 12sqrt6

8 x 12sqrt6 = 96sqrt6 = 235.151
[tex]8\sqrt { 864 } \\ \\ =8\sqrt { 36\cdot 24 } \\ \\ =8\sqrt { 36\cdot 4\cdot 6 } \\ \\ =8\sqrt { 36 } \sqrt { 4 } \sqrt { 6 }[/tex]

[tex]\\ \\ =8\cdot 6\cdot 2\cdot \sqrt { 6 } \\ \\ =96\sqrt { 6 } [/tex]