powershell, 302 bytes

Result

WA

Duration

1182ms

Code [DL]

$a =Read-Host
$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

58 47 06
77 87 20
08 57 46
33 04 12

stdout

58 47 06
77 87 20
08 57 46
33 04 12
-7984.66666666667

stderr

strace