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++: #include <bits/stdc++.h>
#include<stdio.h>
using namespace std;
#define FOR(i,k,n) for(int i = (k); i < (n); i++)
#define REP(i,n) FOR(i,0,n)
#define ALL(a) begin(a),end(a)
#define MS(m,v) memset(m,v,sizeof(m))
#define D10  fixed<<setprecision(3)
typedef vector<int> vi;
typedef vector<string> vs;
typedef pair<int, int> P;
typedef long long ll;
const ll INF = 114514810;
const ll MOD = 1000000007;
const double EPS = 1e-8;
struct edge
{
	int from, to, cost;
	bool operator < (const edge& e) const { return cost < e.cost; }
	bool operator >(const edge& e) const { return cost > e.cost; }
};
int dx[] = { -1, 0, 0, 1 }; int dy[] = { 0, -1, 1, 0 };
template<class T> T &chmin(T &a, const T &b) { return a = min(a, b); }
template<class T> T &chmax(T &a, const T &b) { return a = max(a, b); }
bool valid(int x, int y, int h, int w) { return (x >= 0 && y >= 0 && x < h&&y < w); }
///*************************************************************************************///
///*************************************************************************************///
///*************************************************************************************///

const double PI = acos(-1.0);
bool eq(double a, double b) { return fabs(a - b) < EPS; }
typedef complex<double> Point;
typedef vector<Point> Polygon;

namespace std
{
	bool operator < (const Point& a, const Point& b)
	{
		return real(a) != real(b) ? real(a) < real(b) : imag(a) < imag(b);
	}
}

struct Line
{
	Point a, b;
	Line(Point p, Point q) :a(p), b(q) {};
};

struct Circle
{
	Point p; double r;
	Circle(Point a, double b) :p(a), r(b) {};
};

double dot(Point a, Point b)
{
	return real(conj(a)*b);
}

double cross(Point a, Point b)
{
	return imag(conj(a)*b);
}

int ccw(Point a, Point b, Point c)
{
	b -= a; c -= a;
	if (cross(b, c) > EPS) return 1;	//counter cloclwise
	if (cross(b, c) < -EPS) return -1;  //cloclwise
	if (dot(b, c) < 0) return 2;		//c--a--b on line 
	if (norm(b) < norm(c)) return -2;   //a--b--c on line
	return 0;							//a--c--b on line
}

bool isis_ll(Line l, Line m)
{
	return abs(cross(l.b - l.a, m.b - m.a)) > EPS;
}

bool isis_ls(Line l, Line s)
{
	return cross(l.b - l.a, s.a - l.a)*cross(l.b - l.a, s.b - s.a) < EPS;
}

bool isis_ss(Line s, Line t)
{
	return (ccw(s.a, s.b, t.a)*ccw(s.a, s.b, t.b) <= 0 &&
		ccw(t.a, t.b, s.a)*ccw(t.a, t.b, s.b) <= 0);
}

bool isis_lp(Line l, Point p)
{
	return (abs(cross(l.b - p, l.a - p)) < EPS);
}

bool isis_sp(Line s, Point p)
{
	return (abs(s.a - p) + abs(s.b - p) - abs(s.b - s.a)) < EPS;
}

Point projection(Line l, Point p)
{
	Point base = l.b - l.a;
	double r = dot(p - l.a, base) / norm(base);
	return l.a + base*r;
}

Point mirror(Line l, Point p)
{
	return 2.0*projection(l, p) - p;
}

double dist_lp(Line l, Point p)
{
	return abs(p - projection(l, p));
}

double dist_ll(Line l, Line m)
{
	return isis_ll(l, m) ? 0 : dist_lp(l, m.a);
}

double dist_ls(Line l, Line s)
{
	if (isis_ls(l, s)) return 0;
	return min(dist_lp(l, s.a), dist_lp(l, s.b));
}

double dist_sp(Line s, Point p)
{
	Point r = projection(s, p);
	if (isis_sp(s, r)) return abs(r - p);
	return min(abs(s.a - p), abs(s.b - p));
}

double dist_ss(Line s, Line t)
{
	if (isis_ss(s, t)) return 0;
	return min(min(dist_sp(s, t.a), dist_sp(s, t.b)), min(dist_sp(t, s.a), dist_sp(t, s.b)));
}

Point is_ll(Line s, Line t)
{
	double a = cross(s.b - s.a, t.b - t.a);
	double b = cross(s.b - s.a, s.b - t.a);
	return t.a + b / a*(t.b - t.a);
}

int main()
{
	int n;
	cin >> n;
	while (n--)
	{
		double x[3], y[3];
		REP(i, 3) cin >> x[i] >> y[i];
		Point p(x[0], y[0]), q(x[1], y[1]), r(x[2], y[2]);
		Point s = q - p, t = r - p;

		Line a((p + q)*0.5, (p + q)*0.5 + s*Point(0,1));
		Line b((p + r)*0.5, (p + r)*0.5 + t*Point(0,1));
		Point ans = is_ll(a, b);
		printf("%.3lf %.3lf %.3lf\n", ans.real(), ans.imag(), abs(ans - p));
	}
	return 0;
}