#include #include #include #include using namespace std; struct point { double x,y,z; point(double _x,double _y,double _z) { x=_x;y=_y;z=_z; } }; struct Vector { double x,y,z; Vector(double _x,double _y,double _z) { x=_x,y=_y,z=_z; } }; struct plane { double a,b,c,d; plane(double _a,double _b,double _c,double _d) { a=_a,b=_b,c=_c,d=_d; } }; Vector getvector(point a,point b) { Vector ans=Vector(a.x-b.x,a.y-b.y,a.z-b.z); return ans; } Vector Common_Vertical_Line(Vector a,Vector b) { Vector ans=Vector(a.y*b.z-a.z*b.y,a.z*b.x-a.x*b.z,a.x*b.y-a.y*b.x); return ans; } double pointDis(Vector a) { return sqrt((a.x*a.x+a.y*a.y+a.z*a.z)); } plane getPlane(Vector a,Vector b,point c) { Vector line=Common_Vertical_Line(a,b); plane ans=plane(line.x,line.y,line.z,line.x*(-1)*c.x+line.y*(-1)*c.y+line.z*(-1)*c.z); return ans; } point getPoint(plane P,Vector B,point C) { double k=((-1)*P.b*C.y-P.a*C.x-P.c*C.z-P.d)/(P.a*B.x+P.b*B.y+P.c*B.z); point ans=point(B.x*k+C.x,B.y*k+C.y,B.z*k+C.z); return ans; } int main() { int t; scanf("%d",&t); while(t--) { double a,b,c; scanf("%lf%lf%lf",&a,&b,&c);point x1=point(a,b,c); scanf("%lf%lf%lf",&a,&b,&c);point y1=point(a,b,c); scanf("%lf%lf%lf",&a,&b,&c);point x2=point(a,b,c); scanf("%lf%lf%lf",&a,&b,&c);point y2=point(a,b,c); Vector l1=getvector(x1,y1); Vector l2=getvector(x2,y2); Vector line=Common_Vertical_Line(l1,l2); plane p1=getPlane(l1,line,x1); plane p2=getPlane(l2,line,x2); point ans2=getPoint(p1,l2,x2); point ans1=getPoint(p2,l1,x1); Vector ans=getvector(ans1,ans2); printf("%.6lf\n",pointDis(ans)); printf("%.6lf %.6lf %.6lf %.6lf %.6lf %.6lf\n",ans1.x,ans1.y,ans1.z,ans2.x,ans2.y,ans2.z); } return 0; }