Go: package main

import (
	"fmt"
	"math"
)

func main() {
	var num int
	fmt.Scan(&num)
	for i := 0; i < num; i++ {
		var x1, y1, x2, y2, x3, y3 float64
		fmt.Scanf("%f%f%f%f%f%f", &x1, &y1, &x2, &y2, &x3, &y3)

		a := 2 * (x2 - x1)
		b := 2 * (y2 - y1)
		c := 2 * (x3 - x1)
		d := 2 * (y3 - y1)
		e := x2*x2 - x1*x1 + y2*y2 - y1*y1
		f := x3*x3 - x1*x1 + y3*y3 - y1*y1

		// 直線1: ax + by - e = 0
		// 直線2: cx + dy - f = 0
		px := (d*e - b*f) / (a*d - b*c)
		py := (c*e - a*f) / (b*c - a*d)
		r := math.Sqrt((px-x1)*(px-x1) + (py-y1)*(py-y1))
		fmt.Printf("%.3f %.3f %.3f\n", px, py, r)
	}
}

C++: #include <stdio.h>
#include<string>
#include<string.h>
#include <math.h>
#include<iostream>
#include <algorithm>
#include <map>
#include <vector>
#include <queue>
using namespace  std;


/*
//my header
#include "define.h"
#include "geometry.h"*/

#define MyAbs(a) ((a)>0?(a):-(a))
#define MyEqualDoule(a,b) (MyAbs(a-b)<1e-6)

#define foreach(i,n) for(i=0;i<n;++i)
#define foreachd(i,n) for(int i=0;i<n;++i)
#define printfInt1(n) printf("%d\n",n)
#define scanfInt1(n) scanf("%d",&n)
#define scanfInt2(a,b) scanf("%d%d", &a, &b)
#define scanfInt3(a,b,c) scanf("%d%d%d", &a, &b, &c)
#define scanfFloat2(a,b) scanf("%f%f", &a,&b)


void init()
{
#ifdef _WIN32
	freopen("1.txt", "r", stdin);
#endif
}

void func();

int main()
{
	init();
	func();

	return 0;
}



//譁ケ遞?class CMathEquation 
{
public:
	//ax + by = c;dx + ey = d;荳疲婿遞矩怙隕∽ソ晁ッ∵怏隗」
	static void CalcuXY(double&x, double&y, double a, double b, double c, double d,double e,double f)
	{
		x = (c*e-f*b)*1.0/(a*e - b*d);
		y = (c*d-a*f)*1.0/(b*d - a*e);
		if(MyEqualDoule(x, 0))
			x = 0;
		if(MyEqualDoule(y, 0))
			y = 0;
	}

	//蟾イ遏・荳臥せ蟆ア蝨?噪蝨?ソバx?経y蜥悟濠蠕в
	static void CalcuCircleByPoint3(double& ox, double& oy, double& r, double x1, double y1, double x2, double y2,double x3, double y3)
	{
		double a,b,c,d,e,f;

		double dx12,dx13,dy12,dy13,dx12_2,dy12_2,dx13_2,dy13_2;
		dx12 = x1 - x2;
		dx12_2 = dx12 * (x1 + x2);
		dy12 = y1 - y2;
		dy12_2 = dy12 * (y1 + y2);
		dx13 = x1 - x3;
		dx13_2 = dx13 * (x1 + x3);
		dy13 = y1 - y3;
		dy13_2 = dy13 * (y1 + y3);
		
		a = dx12;
		b = dy12;
		c = (dx12_2 + dy12_2) / 2.0;
		d = dy13;
		e = dy13;
		f = (dx13_2 + dy13_2) / 2.0;
		CalcuXY(ox, oy, a, b, c, d, e, f);
		r = pow((ox - x1), 2) + pow((oy - y1), 2);
		r = sqrt(r);
	}
};


void func()
{
	int n;
	scanf("%d", &n);
	while(n--)
	{
		double x1,y1, x2,y2,x3,y3;
		scanf("%lf%lf%lf%lf%lf%lf", &x1, &y1, &x2, &y2, &x3, &y3);
		double ox, oy, r;
		CMathEquation::CalcuCircleByPoint3(ox, oy, r, x1, y1, x2, y2, x3, y3);
		printf("%.3lf %.3lf %.3lf\n", ox, oy, r);
	}
}

C++: #include <iostream>
#include <math.h>
#include <algorithm>
#include <string>
#include <stack>
#include <queue>
#include <set>
#include <cstdio>
#include <string.h>
using namespace std;

#define FOR(i, n) for(int i = 0; i < n; i++)
#define bit(i) static_cast< bitset<8> >(i)

typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> VI;
typedef vector<string> VS;
typedef pair<int, int> PII;
typedef pair<long long, long long>PLL;
typedef queue<int> QI;
typedef priority_queue<int> maxpq;
typedef priority_queue<int, vector<int>, greater<int> > minpq;

struct edge{int to, cost;};

void begin(){cin.tie(0); ios::sync_with_stdio(false);};
int gcd(int a, int b){if(a%b==0){return(b);}else{return(gcd(b,a%b));}};
int lcm(int m, int n){if((0 == m)||(0 == n)){return 0;} return ((m / gcd(m, n)) * n);};
unsigned long long comb(long n, long m){unsigned long long c = 1; m = (n - m < m ? n - m : m);
    for(long ns = n - m + 1, ms = 1; ms <= m; ns ++, ms ++){c *= ns; c /= ms;} return c;};

void cp(int a1[], int a2[], int l){FOR(i, l) a2[i] = a1[i];};
double sq(double d){return d*d;};
int sq(int i){return i*i;};
double sqdist(int x1, int y1, int x2, int y2){
    double dx = x1 - x2, dy = y1 - y2; return dx*dx + dy*dy;
};

// ワーシャルフロイド法
void warshallFloyd(int d[100][100], int n){
    for(int k = 0; k < n; ++k)
        for(int i = 0; i < n; ++i)
            for(int j = 0; j < n; ++j)
                if(d[i][k] != -1 && d[k][j] != -1){
                    if(d[i][j] == -1){
                        d[i][j] = d[i][k] + d[k][j];
                    }else{
                        d[i][j] = min(d[i][j], d[i][k] + d[k][j]);
                    }
                }
};


// d:隣接行列  n:グラフのサイズ  s:始点  dist:始点からの距離が入る配列
void dijkstra(int d[1000][1000], int n, int s, int dist[1000]){
    FOR(i, n) dist[i] = -1;
    dist[s] = 0;
    priority_queue<PII, vector<PII>, greater<PII> > q;
    q.push(PII(0, s));
    while (!q.empty()) {
        PII p = q.top(); q.pop();
        int i = p.second;
        if(dist[i] < p.first) continue;
        for(int j = 0; j < n; j++){
            if(d[i][j] == -1) continue;
            if(dist[j] == -1){
                dist[j] = dist[i] + d[i][j];
                q.push(PII(dist[j], j));
            }else if(dist[j] > dist[i] + d[i][j]){
                dist[j] = dist[i] + d[i][j];
                q.push(PII(dist[j], j));
            }
        }
    }
};

// 線分の交差判定
bool isCross(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4){
    // 並行な場合
    int m = (x2-x1)*(y4-y3)-(y2-y1)*(x4-x3);
    if(m == 0) return false;
    // 媒介変数の値が0より大きく1以下なら交差する、これは問題の状況によって変わるかも。
    double r =(double)((y4-y3)*(x3-x1)-(x4-x3)*(y3-y1))/m;
    double s =(double)((y2-y1)*(x3-x1)-(x2-x1)*(y3-y1))/m;
    return (0 < r && r <= 1 && 0 < s && s <= 1);
};

// 外積の計算 AB CD の内積を求める
int crossProdct(int ax, int ay, int bx, int by, int cx, int cy, int dx, int dy){
    int abx = bx - ax; int aby = by - ay;
    int cdx = dx - cx; int cdy = dy - cy;
    return abx * cdy - cdx * aby;
};
double crossProdct(double ax, double ay, double bx, double by, double cx, double cy, double dx, double dy){
    double abx = bx - ax; double aby = by - ay;
    double cdx = dx - cx; double cdy = dy - cy;
    return abx * cdy - cdx * aby;
};
double innerProduct(double ax, double ay, double bx, double by, double cx, double cy, double dx, double dy){
    double abx = bx - ax; double aby = by - ay;
    double cdx = dx - cx; double cdy = dy - cy;
    return abx * cdx + aby * cdy;
};

// 三角形の内部判定 ABCの中にPがあるか判定
bool inTriangle(int ax, int ay, int bx, int by, int cx, int cy, int px, int py){
    int c1 = crossProdct(ax, ay, bx, by, bx, by, px, py);
    int c2 = crossProdct(bx, by, cx, cy, cx, cy, px, py);
    int c3 = crossProdct(cx, cy, ax, ay, ax, ay, px, py);
    return (c1 > 0 && c2 > 0 && c3 > 0) || (c1 < 0 && c2 < 0 && c3 < 0);
};
bool inTriangle(double ax, double ay, double bx, double by, double cx, double cy, double px, double py){
    double c1 = crossProdct(ax, ay, bx, by, bx, by, px, py);
    double c2 = crossProdct(bx, by, cx, cy, cx, cy, px, py);
    double c3 = crossProdct(cx, cy, ax, ay, ax, ay, px, py);
    return (c1 > 0 && c2 > 0 && c3 > 0) || (c1 < 0 && c2 < 0 && c3 < 0);
};

// 三角形の外心
void circumcenter(double ax, double ay, double bx, double by, double cx, double cy, double res[3]){
    // AB AC を求める
    double abx = bx - ax; double aby = by - ay;
    double acx = cx - ax; double acy = cy - ay;
    double m = abx * acy - acx * aby; // 分母 m = 0 となるのは3点が一直線になるとき
    double s = (abx * acx + aby * acy - sq(acx) - sq(acy)) / m; // 媒介変数s
    res[0] = abx / 2 + s * aby / 2; res[1] = aby / 2 - s * abx / 2;
    // cout << res[0] << " " << res[1] << endl;
    res[2] = sqrt(sqdist(0, 0, res[0], res[1]));
    res[0] += ax; res[1] += ay;
};




/**
 * start
 * @author yoshikyoto
 */
int main(int argc, const char * argv[]){
    begin();
    int n;
    cin >> n;
    FOR(i, n){
        double x1, y1, x2, y2, x3, y3;
        cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
        double res[3];
        circumcenter(x1, y1, x2, y2, x3, y3, res);
        res[0] *= 1000; res[1] *= 1000; res[2] *= 1000;
        double x = round(res[0]), y = round(res[1]), r = round(res[2]);
        printf("%.3f %.3f %.3f\n", x / 1000.0, y / 1000.0, r / 1000.0);
    }
}