nadesiko, 252 bytes

Result

WA

Duration

727ms

Code [DL]

a=f=[]i=-2
標準入力取得した時には(s)
t=sを" "で区切る
i=i+1
もしi<0ならf=t
違えばa[3*i]=t@0-f@0
a[3*i+1]=t@1-f@1
a[3*i+2]=t@2-f@2
もしi=2なら(a@0*a@4*a@8+a@1*a@5*a@6+a@2*a@3*a@7-a@2*a@4*a@6-a@1*a@3*a@8-a@0*a@5*a@7)/6と表示

stdin

40 91 18
76 54 85
03 70 29
48 17 10

stdout

stderr

undefined:28
__v0.line=6;__varslist[2]["a"][(parseFloat((parseFloat(3) * parseFloat(__varslist[2]["i"]))) + parseFloat(1))] = (parseFloat(__vars["t"][1]) - parseFloat(__vars["f"][1]));
                                                                                                               ^

TypeError: Cannot create property '-2' on boolean 'false'
    at eval (eval at _run (/usr/lib/node_modules/nadesiko3/src/nako3.js:149:7), <anonymous>:28:112)
    at Interface.<anonymous> (/usr/lib/node_modules/nadesiko3/src/plugin_node.js:470:9)
    at emitOne (events.js:116:13)
    at Interface.emit (events.js:211:7)
    at Interface._onLine (readline.js:282:10)
    at Interface._normalWrite (readline.js:424:12)
    at ReadStream.ondata (readline.js:141:10)
    at emitOne (events.js:116:13)
    at ReadStream.emit (events.js:211:7)
    at addChunk (_stream_readable.js:263:12)

strace