php, 221 bytes

Result

WA

Duration

502ms

Code [DL]

<?=[$a,$b,$c,$d,$e,$f,$g,$h,$i,$j,$k,$l]=explode(" ",readline()." ".readline()." ".readline()." ".readline()),$g-=$a,$h-=$b,$i-=$c,$j-=$a,$k-=$b,$l-=$c,(($e-$b)*($i*$j-$g*$l)+($f-$c)*($g*$k-$h*$j)+($d-$a)*($h*$l-$i*$k))/6

stdin

41 75 86
43 09 42
52 24 27
93 34 75

stdout

stderr

PHP Parse error:  syntax error, unexpected end of file, expecting ',' or ';' in /volume/CODE on line 1

strace