#include <iostream>
#include <cmath>
#include <cstdio>
using namespace std;
int main (){
    int n;
    cin>>n;
    while(n--){
        double x1 ,y1,x2,y2;
        cin>>x1>>y1>>x2>>y2;
        double num=(x1-x2)*(x1-x2)+(y1-y2)*(y1-y2);
        printf("%.2lf\n",sqrt(num));
    }
    return 0;
}

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

#include<stdio.h>

#include<math.h>

int main(){

double x1,y1,x2,y2,m;

int n;

scanf("%d",&n);

while(n--){

scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);

m=(x1-x2)(x1-x2)+(y1-y2)(y1-y2);

m=sqrt(m);

printf("%.2f\n",m);

}

return 0;

}

#include <stdio.h>

#include <math.h>

int main()

{

int n;

scanf("%d",&n);

for(int i=0;i<n;i++){

double x1,y1,x2,y2;

scanf("%lf %lf %lf %lf",&x1,&y1,&x2,&y2);

double a=sqrt((x1-x2)(x1-x2)+(y1-y2)(y1-y2));

printf("%.2lf\n",a);

}

return 0;

}

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