#include #include #define Pi 3.141592653 int main() { int t; scanf("%d",&t); while(t--) { double x1,y1,x2,y2; scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2); double ans=0; ans=acos( ((x1*x1 + y1*y1 + x2*x2 + y2*y2- (x1-x2)*(x1-x2) - (y1-y2)*(y1-y2) )/(2* sqrt(x1*x1 + y1*y1) * sqrt(x2*x2 + y2*y2) )))*180/Pi; printf("%.2lf\n",ans); } return 0; }