NF>=9 { ax=$4-$1; ay=$5-$2; az=$6-$3;
        bx=$7-$1; by=$8-$2; bz=$9-$3;
        if ((cx=ay*bz-az*by)<0) cx=(-cx);
        if ((cy=az*bx-ax*bz)<0) cy=(-cy);
        if ((cz=ax*by-ay*bx)<0) cz=(-cz);
        SA1+=sqrt(cx^2+cy^2+cz^2); SA2+=(cx+cy+cz) }
END { printf "%g\t%g\t%g\n",SA1/2,SA2/2,SA2/SA1 }