Go: package main

import (
	"bufio"
	"fmt"
	"io"
	"math"
	"os"
	"strconv"
	"strings"

)


func main() {
	solve(os.Stdin, os.Stdout)
}

type ReaderEx struct {
	baseScanner *bufio.Scanner
	words       []string
	nextWordIdx func() int
	initWordIdx func(int)
}

func NewScannerEx(stdin io.Reader) *ReaderEx {
	var this ReaderEx
	var idx int
	var wordsCnt int
	this.baseScanner = bufio.NewScanner(stdin)
	this.baseScanner.Buffer(make([]byte, 0), 1E+11)
	this.nextWordIdx = func() int {
		cur := idx
		idx = (idx + 1) % wordsCnt
		return cur
	}
	this.initWordIdx = func(wc int) {
		idx = 0
		wordsCnt = wc
	}
	return &this
}

func (me *ReaderEx) Scan(doSplit bool) (isScanned bool) {
	isScanned = me.baseScanner.Scan()
	if doSplit {
		me.words = strings.Fields(me.baseScanner.Text())
	} else {
		me.words = []string{me.baseScanner.Text()}
	}
	me.initWordIdx(len(me.words))
	return
}

func (me *ReaderEx) nextBytes() []byte {
	return []byte(me.words[me.nextWordIdx()])
}
func (me *ReaderEx) nextString() string {
	return me.words[me.nextWordIdx()]
}

type StringArray []string

func (me *ReaderEx) nextStringArray() StringArray {
	return me.words[me.nextWordIdx():]
}

func (me StringArray) toStrings() []string {
	return me
}

func (me StringArray) toInts() []int {
	strValues := me.toStrings()
	values := make([]int, len(strValues))
	for i, v := range strValues {
		n, err := strconv.Atoi(v)
		if err != nil {
			panic(err)
		}
		values[i] = n
	}
	return values
}
func (me *ReaderEx) nextInt() int {
	n, err := strconv.Atoi(me.words[me.nextWordIdx()])

	defer func() {
		if err != nil {
			panic(fmt.Sprintf("getInt(%d)", n))
		}
	}()
	return n
}

func pow(x, y, mod int) (ans int) {

	ans = 1
	for bit := 1 << uint(math.Floor(math.Log2(float64(y)))); ; bit >>= 1 {
		if y&bit != 0 {
			ans *= x
			if mod > 0 {
				ans %= mod
			}
		}
		if bit <= 1 {
			return
		}
		ans *= ans
		if mod > 0 {
			ans %= mod
		}
	}
}

type factType struct {
	prime int
	count int
}

func fact(n int) (facts []*factType) {

	for i := 2; i*i <= n; i++ {
		if n%i == 0 {
			fa := factType{prime: i}
			for n%fa.prime == 0 {
				n /= fa.prime
				fa.count++
			}
			facts = append(facts, &fa)
		}
	}
	if n > 1 {
		facts = append(facts, &factType{prime: n, count: 1})
	}
	return facts
}
func dec2bin(n int) (ret []bool) {
	for bit := 1 << uint(math.Floor(math.Log2(float64(n)))); ; bit >>= 1 {
		ret = append(ret, n&bit != 0)

		if bit <= 1 {
			return
		}
	}

}

func abs(v int) int {
	if v < 0 {
		v = -v
	}
	return v
}

func b2i(b bool) (i int) {
	if b {
		i = 1
	} else {
		i = 0
	}
	return
}

func solve(stdin io.Reader, stdout io.Writer) {

	r := NewScannerEx(stdin)
	r.Scan(true)
	n := r.nextInt()

	type Vec struct {
		x, y float64
	}
	vec := func(a, b Vec) Vec { return Vec{b.x - a.x, b.y - a.y} }
	unv := func(a Vec) Vec { return Vec{-a.y, a.x} }
	cdot := func(a, b Vec) float64 { return a.x*b.x + a.y*b.y }
	times := func(t float64, a Vec) Vec { return Vec{t * a.x, t * a.y} }
	add := func(a, b Vec) Vec { return Vec{a.x + b.x, a.y + b.y} }
	for i := 0; i < n; i++ {

		r.Scan(true)
		nextFloat64 := func() (ret float64) { fmt.Sscanf(r.nextString(), "%f", &ret); return }
		a1, a2, a3 := Vec{nextFloat64(), nextFloat64()}, Vec{nextFloat64(), nextFloat64()}, Vec{nextFloat64(), nextFloat64()}
		unv23 := unv(vec(a2, a3))
		v12 := vec(a1, a2)
		v31 := vec(a3, a1)
		s := cdot(v12, v31) / 2 / cdot(v12, unv23)
		c := add(times(.5, add(a2, a3)), times(s, unv23))
		v1c := vec(a1, c)
		fmt.Fprintf(stdout, "%.3f %.3f %.3f\n", c.x, c.y, math.Sqrt(v1c.x*v1c.x+v1c.y*v1c.y))
	}
}

C++: /* {{{ Shinobu kawaii */
/*
  ______   __        _                  __                 
.' ____ \ [  |      (_)                [  |                
| (___ \_| | |--.   __   _ .--.   .--.  | |.--.   __   _   
 _.____`.  | .-. | [  | [ `.-. |/ .'`\ \| '/'`\ \[  | | |  
| \____) | | | | |  | |  | | | || \__. ||  \__/ | | \_/ |, 
 \______.'[___]|__][___][___||__]'.__.'[__;.__.'  '.__.'_/ 
                                                           
*/
/* }}} */
/* include {{{ */
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include <algorithm>
#include <utility>
#include <set>
#include <map>
#include <stack>
#include <queue>
#include <deque>
#include <functional>
using namespace std;
/* }}} */

// #define int long long

/* cpp template {{{ */
/* short */
#define pb push_back
#define mp make_pair
#define print(x) cout << x << '\n'
#define Fi first
#define Se second

/* REPmacro */
#define REPS(i, a, n) for (int i = (a); i < (n); i++)
#define REP(i, n) for (int i = 0; i < (n); i++)
#define RREP(i, n) for (int i = 1; i <= (n); i++)
#define DEPS(i, a, n) for (int i = (a); i >= n; i--)
#define DEP(i, n) for (int i = (n); i >= 0; i--)

/* typedef */
typedef long long ll;
typedef unsigned long long ull;
typedef vector<int> vi;
typedef vector<vector<int> > vii;
typedef pair<int, int> pii;

/* const */
const int INF = 999999999;
const double EPS = 1e-9;
const int dx[] = {0, 1, 0, -1, 1, -1, 1, -1}, dy[] = {1, 0, -1, 0, 1, -1, -1, 1};

/* func */
inline bool is_uruu(int y) {return (y % 4 == 0 && (y % 100 != 0 || y % 400 == 0));}
inline bool inside(int y, int x, int H, int W) {return (y >= 0 && x >= 0 && y < H && x < W);}

/* }}} */

typedef pair<double, double> pdd;

#define sq(x) ((x) * (x))

signed main()
{
  cin.tie(0);
  ios::sync_with_stdio(false);

  int n;
  cin >> n;

  while (n--){
    double x1, y1, x2, y2, x3, y3;
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;

    double a = 2 * (x1 - x2), b = 2 * (y1 - y2),
           c = 2 * (x1 - x3), d = 2 * (y1 - y3);

    double y = (c * (sq(x1) * sq(y1) - sq(x2) - sq(y2)) - a * (sq(x1) + sq(y1) - sq(x3) - sq(y3))) / (c * b == a * d ? EPS : c * b - a * d);
    double x = (sq(x1) + sq(y1) - sq(x3) - sq(y3) - d * y) / (c == 0 ? EPS : c);
    double r = sqrt(sq(x - x1) + sq(y - y1));
    printf("%.3f %.3f %.3f\n", x, y, r);
  }

  return (0);
}

C++: #include <bits/stdc++.h>
using namespace std;

int main() {
  int n;
  double a, b, c, d, e, f, px, py, r;
  cin >> n;
  for (int i = 0; i < n; i++) {
    cin >> a >> b >> c >> d >> e >> f;
    py = ((e - a) * (a * a + b * b - c * c - d * d) -
          (c - a) * (a * a + b * b - e * e - f * f)) /
         (2 * (e - a) * (b - d) - 2 * (c - a) * (b - f));
    if (c != a) {
      px = (2 * (b - d) * py - a * a - b * b + c * c + d * d) / (2 * (c - a));
    } else {
      px = (2 * (b - f) * py - a * a - b * b + e * e + f * f) / (2 * (e - a));
    }
    r = hypot(px - a, py - b);
    cout << fixed << setprecision(3) << px << " " << py << " " << r << endl;
  }
}

C++: #include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int main()
{
	int n;cin>>n;
	double x1,x2,x3,y1,y2,y3,x12,x13,y12,y13,xx12,yy12,xx13,yy13,x,y,r;
	for(int i=0;i<n;i++)
	{
		cin>>x1>>y1>>x2>>y2>>x3>>y3;
		
		x12=x1-x2;
		x13=x1-x3;
		y12=y1-y2;
		y13=y1-y3;
		xx12=x1*x1-x2*2;
		xx13=x1*x1-x3*x3;
		yy12=y1*y1-y2*y2;
		yy13=y1*y1-y3*y3;
		
		x=-0.5*(y12*(xx13+yy13)-y13*(xx12+yy12))/(x12*y13-x13*y12);
		y=-0.5*(x12*(xx13+yy13)-x13*(xx12+yy12))/(y12*x13-y13*x12);
		r=sqrt(x*x+y*y+x1*x1+y1*y1-2*x*x1-2*y*y1);
		
		printf("%.3lf %.3lf %.3lf\n",x,y,r);
		
	}
	return 0;
}

C++: #include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;


int main(){
	int n;
	double x[3];
	double y[3];
	double p, q, r;

	cin >> n;
	while (n--){
		for (int i = 0; i < 3; i++) cin >> x[i] >> y[i];

		double a = y[0] - y[2];
		double b = y[0] - y[1];
		double c = x[0] - x[2];
		double d = x[0] - x[1];
		double e = pow(y[0], 2) - pow(y[1], 2) + pow(x[0], 2) - pow(x[1], 2);
		double f = pow(y[0], 2) - pow(y[2], 2) + pow(x[0], 2) - pow(x[2], 2);

		p = ((a*e) - (b*f)) / (2 * a*d - 2 * b*c);
		q = ((c*e) - (d*f)) / (2 * c*b - 2 * d*a);
		r = sqrt(pow(p - x[0], 2) + pow(q - y[0], 2));

		printf("%.3lf %.3lf %.3lf\n", p, q, r);
	}

	return 0;
}