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: import math

n = int(input())
for i in range(n):
    x1, y1, x2, y2, x3, y3 = map(float, input().split())
    a1 = x1 ** 2 - x2 ** 2 + y1 ** 2 - y2 ** 2
    a2 = y1 ** 2 - y3 ** 2 + x1 ** 2 - x3 ** 2
    px = ((y1 - y3) * a1 - (y1 - y2) * a2) / \
        (2 * (y1 - y3) * (x1 - x2) - 2 * (y1 - y2) * (x1 - x3))
    py = ((x1 - x3) * a1 - (x1 - x2) * a2) / \
        (2 * (x1 - x3) * (y1 - y2) - 2 * (x1 - x2) * (y1 - y3))
    r = math.hypot(x1 - px, y1 - py)
    print("{0:.3f} {1:.3f} {2:.3f}".format(px, py, r))

Python: import math
n = int(input())
    
for i in range(n) :
    x1, y1, x2, y2, x3, y3 = map(float, input().split())
    py = ((x3-x1)*(x1**2 + y1**2 - x2**2 - y2**2) - (x2-x1)*(x1**2 + y1**2 - x3**2 - y3**2)) / (2*(x3-x1)*(y1-y2) - 2*(x2-x1)*(y1-y3))
    if x1 == x2 :
        px = (2*(y1-y3)*py - x1**2 - y1**2 + x3**2 + y3**2) / (2*(x3 - x1))
    else :
        px = (2*(y1-y2)*py - x1**2 - y1**2 + x2**2 + y2**2) / (2*(x2 - x1))
    r = math.sqrt((px - x1)**2 + (py -y1)**2)

    print('{:.3f}'.format(px), '{:.3f}'.format(py), '{:.3f}'.format(r))

Python: import math
deta=[float(i) for i in input().split()]
h1=math.sqrt((deta[2]-deta[0])**2+(deta[3]-deta[1])**2)
h2=math.sqrt((deta[4]-deta[2])**2+(deta[5]-deta[3])**2)
h3=math.sqrt((deta[0]-deta[4])**2+(deta[1]-deta[5])**2)
sub=(h1+h2+h3)/2
s=math.sqrt(sub*(sub-h1)*(sub-h2)*(sub-h3))
sum=((h1*h2*h3)/s)/4

a=2*deta[2]-2*deta[0]
b=2*deta[3]-2*deta[1]
c=-(deta[0]**2+deta[1]**2-(deta[2]**2)-(deta[3]**2))
d=2*deta[4]-2*deta[2]
e=2*deta[5]-2*deta[3]
f=-(deta[2]**2+deta[3]**2-(deta[4]**2)-(deta[5]**2))

x=(e*c-b*f)/(a*e-b*d)
y=(a*f-c*d)/(a*e-b*d)
print("{0:.3f} {1:.3f} {2:.3f}".format(x,y,sum))

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: import math
for i in range(int(input())):
    x1,y1,x2,y2,x3,y3 = map(float,input().split())
    
    a = 2*(x2 - x1)
    b = 2*(y2 - y1)
    c = x1**2 - x2**2 + y1**2 - y2**2
    
    aa = 2*(x3 - x1)
    bb = 2*(y3 - y1)
    cc = x1**2 - x3**2 + y1**2 - y3**2

    x = (b*cc - bb*c) / (a*bb - aa*b)
    y = (c*aa - cc*a) / (a*bb - aa*b)
    
    r = math.hypot(x1 - x,y1 - y)
            
    print(f'{x:.03f} {y:.03f} {r:.03f}')

Python: import sys
import math
n = int(sys.stdin.readline().rstrip())
for i in range(n):
    x1,y1,x2,y2,x3,y3 = map(float, sys.stdin.readline().rstrip().split(' '))
    p = ((y1-y3)*(y1**2-y2**2+x1**2-x2**2)-(y1-y2)*(y1**2-y3**2+x1**2-x3**2)) / (2*(y1-y3)*(x1-x2)-2*(y1-y2)*(x1-x3))
    q = ((x1-x3)*(x1**2-x2**2+y1**2-y2**2)-(x1-x2)*(x1**2-x3**2+y1**2-y3**2)) / (2*(x1-x3)*(y1-y2)-2*(x1-x2)*(y1-y3))
    r = math.sqrt((p-x1)**2 + (q-y1)**2)
    print("{:0.3f} {:0.3f} {:0.3f}".format(round(p,3),round(q,3),round(r,3)))

Python: def main():
	import math
	n = int(input())
	w = [0]*6

	for _ in range(n):
		x1, y1, x2, y2, x3, y3 = map(float, input().split())
		w[0] = 2*(x2-x1)
		w[1] = 2*(y2-y1)
		w[2] = x1**2 + y1**2 - x2**2 - y2**2
		w[3] = 2*(x3-x1)
		w[4] = 2*(y3-y1)
		w[5] = x1**2 + y1**2 - x3**2 - y3**2

		x, y = solve(w)

		r = math.hypot((x-x1), (y-y1))

		print("{:.3f} {:.3f} {:.3f}".format(x, y, r))


def solve(w):
	x = (w[2]*w[4]-w[1]*w[5]) / (w[0]*w[4]-w[1]*w[3])
	y = (w[2]*w[3]-w[0]*w[5]) / (w[1]*w[3]-w[0]*w[4])
	x = round(x, 3)
	y = round(y, 3)
	if x == -0.0:
	    x = 0.0
	if y == -0.0:
	    y = 0.0
	return x, y


if __name__ == '__main__':
	main()