powershell, 310 bytes

Result

WA

Duration

999ms

Code [DL]

$a =Read-Host.Split()
$b =(Read-Host).Split()
$c =(Read-Host).Split()
$d =(Read-Host).Split()
$x=@()
$y=@()
$z=@()
foreach($i in 0..2){
$x+=$b[$i]-$a[$i]
$y+=$c[$i]-$a[$i]
$z+=$d[$i]-$a[$i]
}

echo(($x[0]*$y[1]*$z[2]+$x[1]*$y[2]*$z[0]+$x[2]*$y[0]*$z[1]-$x[1]*$y[0]*$z[2]-$x[2]*$y[1]*$z[0]-$x[0]*$y[2]*$z[1])/6)

stdin

54 34 05
41 55 72
91 73 49
03 45 48

stdout

stderr

At line:1 char:21
+ $a =Read-Host.Split()
+                     ~
An expression was expected after '('.
+ CategoryInfo          : ParserError: (:) [], ParentContainsErrorRecordException
+ FullyQualifiedErrorId : ExpectedExpression
 

strace