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))
	}
}

Python: from decimal import Decimal
import math
for _ in range(int(input())):
    x1,y1,x2,y2,x3,y3=list(map(Decimal,input().split()))
    a=x1-x3
    b=y2-y3
    c=x2-x3
    d=y1-y3
    e=y1-y2
    f=x1+x3
    g=x2+x3
    X=(b*d*e+a*b*f-c*d*g)/2/(a*b-c*d)
    try:
        Y=-(a/d)*(X-f/2)+(y1+y3)/2
    except:
        Y=-(c/b)*(X-g/2)+(y2+y3)/2
    R=math.sqrt((x1-X)**2+(y1-Y)**2)
    print(" ".join(["{:.3f}".format(i) for i in [X,Y,R]]))

Python: from decimal import Decimal
import math
for _ in range(int(input())):
    x1,y1,x2,y2,x3,y3=list(map(Decimal,input().split()))
    a=x1-x3
    b=y2-y3
    c=x2-x3
    d=y1-y3
    e=y1-y2
    f=x1+x3
    g=x2+x3
    X=(b*d*e+a*b*f-c*d*g)/2/(a*b-c*d)
    try:
        Y=-(a/d)*(X-f/2)+(y1+y3)/2
    except:
        Y=-(c/b)*(X-g/2)+(y2+y3)/2
    R=math.sqrt((x1-X)**2+(y1-Y)**2)
    print(" ".join(["{:.3f}".format(i) for i in [X,Y,R]]))

Python: from math import sqrt

def circle(x1, y1, x2, y2, x3, y3):
    if x1 == 0:
        dx = 1
        x1 = x1 + dx
        x2 = x2 + dx
        x3 = x3 + dx
    else:
        dx = 0
    if y2 == 0:
        dy = 1
        y1 = y1 + dy
        y2 = y2 + dy
        y3 = y3 + dy
    else:
        dy = 0
    A = [[x1, y1, 1, 1, 0, 0],[x2, y2, 1, 0, 1, 0],[x3, y3, 1, 0, 0, 1]]
#    print(A)
    for i in range(3):
        A[0] = [x/A[0][0] for x in A[0]]
        A[1] = [A[1][j] - A[1][0] * A[0][j] for j in range(6)]
        A[2] = [A[2][j] - A[2][0] * A[0][j] for j in range(6)]
#        print(A)
        for j in range(3):
            A[j] = A[j][1:] + A[j][:1]
        A = A[1:] + A[:1]
#        print(A)
    for i in range(3):
        A[i] = A[i][:3]
#    print(A)
    V = [-x1**2-y1**2, -x2**2-y2**2, -x3**2-y3**2]
    M = [(A[i][0] * V[0] + A[i][1] * V[1] + A[i][2] * V[2]) for i in range(3)]
    xcenter = -0.5 * M[0] - dx
    ycenter = -0.5 * M[1] - dy
    radius = sqrt((M[0]**2) /4 + (M[1]**2) /4 - M[2])
    return xcenter, ycenter, radius

n = int(input())
for line in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, input().split())
    xc, yc, ra = circle(x1, y1, x2, y2, x3, y3)
    print(xc, yc,ra)

Python: n = int(input())
ans = []
for i in range(n):
    ax,ay,bx,by,cx,cy = map(float, input().split(" "))
    a,b,c = 2*(ax-bx),2*(ay-by),(ax+bx)*(ax-bx)+(ay+by)*(ay-by)
    d,e,f = 2*(ax-cx),2*(ay-cy),(ax+cx)*(ax-cx)+(ay+cy)*(ay-cy)
    det = a*e-b*d
    px = (c*e-b*f)/det
    py = (a*f-c*d)/det
    if abs(px) < 1e-4:
        px = 0.0
    if abs(py) < 1e-4:
        py = 0.0
    r = ((ax-px)**2+(ay-py)**2)**(1/2)
    ans.append([px,py,r])
for i in range(n):
    print("{0:.3f}".format(ans[i][0]),"{0:.3f}".format(ans[i][1]),"{0:.3f}".format(ans[i][2]))

Python: def simultaneous_equasion(a, b, c, d, e, f):
    "??£???????¨????"
    det = a * d - b * c
    a11 = d / det
    a12 = - b / det
    a21 = - c / det
    a22 = a / det
    return a11 * e + a12 * f, a21 * e + a22 * f

n = int(input())
for i in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, input().split())
    # (x1, y1), (x2, y2)????????´????????????
    # 2 * (x2 - x1) * x + 2 * (y2 - y1) * y = (y2 - y1) ^ 2 + (x2 - x1) ^ 2
    a = 2 * (x2 - x1)
    b = 2 * (y2 - y1)
    c = 2 * (x3 - x1)
    d = 2 * (y3 - y1)
    e = (y2 - y1) ** 2 + (x2 - x1) ** 2
    f = (y3 - y1) ** 2 + (x3 - x1) ** 2
    px, py = simultaneous_equasion(a, b, c, d, e, f)
    print("%.3f %3f" % (round(px, 3), round(py, 3)))

Python: for _ in[0]*int(input()):
 a,b,c,d,e,f=map(float,input().split())
 x=((a*a+b*b)*(d-f)+(c*c+d*d)*(f-b)+(e*e+f*f)*(b-d))/2/(a*(d-f)+c*(f-b)+e*(b-d))
 y=((a*a+b*b)*(c-e)+(c*c+d*d)*(e-a)+(e*e+f*f)*(a-c))/2/(b*(c-e)+d*(e-a)+f*(a-c))
 print(f"{x:.3f} {y:.3f} {(x*x+y*y)**.5:.3f}")