#include<stdio.h>#include<math.h>int main(){ int n; scanf("%d",&n); while(n--) { float x1,y1,x2,y2,d; scanf("%f%f%f%f",&x1,&y1,&x2,&y2); d=(x2-x1)*(x2-x1)+(y2-y1)*(y2-y1); printf("%.2f\n",sqrt(d)); } return 0;}