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++: /* ??????w */

#include <cstdio>
#include <cmath>
#include <utility>
using namespace std;

#define double long double

struct Line {
  double a;
  double b;
  double c;
};

typedef pair<double, double> Pair;

int n;
double xs[3];
double ys[3];

double Dist(Pair p1, Pair p2) {
  double dx = p1.first - p2.first;
  double dy = p1.second - p2.second;
  return sqrtl(dx*dx+dy*dy);
}

Pair Intersect(Line &l1, Line &l2) {
  double a1 = l1.a;
  double b1 = l1.b;
  double c1 = l1.c;
  double a2 = l2.a;
  double b2 = l2.b;
  double c2 = l2.c;
  double x = (b1*c2 - b2*c1)/(a1*b2-a2*b1);
  double y = (a1*c2 - a2*c1)/(a2*b1-a1*b2);
  return Pair(x, y);
}

int main() {
  scanf("%d", &n);
  while (n--) {
    for (int i=0; i<3; i++) {
      float x, y;
      scanf("%f%f", &x, &y);
      xs[i] = x;
      ys[i] = y;
    }

    Line l1, l2;
    l1.a = xs[1]-xs[0];
    l1.b = ys[1]-ys[0];
    l1.c = -(xs[1]*xs[1]-xs[0]*xs[0] + ys[1]*ys[1]-ys[0]*ys[0])/2;
    l2.a = xs[2]-xs[1];
    l2.b = ys[2]-ys[1];
    l2.c = (xs[1]*xs[1]-xs[2]*xs[2] + ys[1]*ys[1]-ys[2]*ys[2])/2;
    Pair p = Intersect(l1, l2);
    double r = Dist(p, Pair(xs[0], ys[0]));
    p.first = int(p.first*1000+0.5)/1000.0;
    p.second = int(p.second*1000+0.5)/1000.0;
    r = int(r*1000+0.5)/1000.0;
    printf("%.3f %.3f %.3f\n", float(p.first), float(p.second), float(r));
  }
}

C++: #include <iostream>

using namespace std;

int main(void){
	int val;
	while(cin >> val)
		cerr << val << endl;

	return 0;
}

C++: #include <iostream>
#include <stdio.h>
#include <cmath>
using namespace std;

int main() {
	int n, i;
	double x[4], y[4], a[2], b[2], c[2], r;
	cin >> n;
	for (i = 0;i < n;i++) {
		cin >> x[1] >> y[1] >> x[2] >> y[2] >> x[3] >> y[3];

		a[0] = 2.0*(x[2] - x[1]);
		b[0] = 2.0*(y[2] - y[1]);
		c[0] = x[1] * x[1] - x[2] * x[2] + y[1] * y[1] - y[2] * y[2];
		a[1] = 2.0 * (x[3] - x[1]);
		b[1] = 2.0*(y[3] - y[1]);
		c[1] = x[1] * x[1] - x[3] * x[3] + y[1] * y[1] - y[3] * y[3];

		x[0] = (b[0] * c[1] - b[1] * c[0]) / (a[0] * b[1] - a[1] * b[0]);
		y[0] = (c[0] * a[1] - c[1] * a[0]) / (a[0] * b[1] - a[1] * b[0]);

		r = sqrt((x[1] - x[0])*(x[1] - x[0]) + (y[1] - y[0])*(y[1] - y[0]));
		printf("%.3f %.3f %.3f\n", x[0], y[0], r);
	}
}

C++: #include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
#include <map>
#include <algorithm>

#define rep(i, j) FOR(i, 0, j)
#define FOR(i, j, k) for(int i = j; i < k; ++i)
#define SQ(i) ((i) * (i))
using namespace std;

int main(){
  double x1, y1, x2, y2, x3, y3;
  double a1, b1, c1, a2, b2, c2, x, y, a, b, c, cos_a, sin_a, r;
  int n;
  scanf("%d", &n);
  while(n--){
    scanf("%lf%lf%lf%lf%lf%lf", &x1, &y1, &x2, &y2, &x3, &y3);
    a1 = 2 * (x2 - x1); a2 = 2 * (x3 - x1);
    b1 = 2 * (y2 - y1); b2 = 2 * (y3 - y1);
    c1 = SQ(x1) - SQ(x2) + SQ(y1) - SQ(y2);
    c2 = SQ(x1) - SQ(x3) + SQ(y1) - SQ(y3);
    x = (b1 * c1 - b2 * c1) / (a1 * b2 - a2 * b1);
    y = (c1 * a2 - c2 * a1) / (a1 * b2 - a2 * b1);

    a = sqrt(SQ(x1 - x2) + SQ(y1 - y2));
    b = sqrt(SQ(x2 - x3) + SQ(y2 - y3));
    c = sqrt(SQ(x3 - x1) + SQ(y3 - y1));
    //    printf("a = %.3f b = %.3f c = %.3f\n", a, b, c);
    cos_a = (SQ(b) + SQ(c) - SQ(a)) / (2 * b * c);
    sin_a = sqrt(1 - SQ(cos_a));
    //    printf("cos_a = %.3f sin_a = %.3f\n", cos_a, sin_a);
    r = a / sin_a;
    r /= 2;
    printf("%.3f %.3f %.3f\n",x, y, r);
  }
  return 0;
}