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 math import *
def g(x):
    y = (int((1000 * abs(x)) * 2 + 1) // 2) / 1000
    if x < 0:
        y *= -1
    return y
def f(x):
    a = (x[2] - x[4]) * (x[1] - x[3]) - (x[0] - x[2]) * (x[3] - x[5])
    b = (x[0] - x[2]) * (x[4] - x[0]) - (x[5] - x[1]) * (x[1] - x[3])
    l = 0.5 * b / a
    X = 0.5 * x[2] + 0.5 * x[4] + l * (x[3] - x[5])
    Y = 0.5 * x[3] + 0.5 * x[5] + l * (x[4] - x[2])
    R = sqrt((X - x[0]) ** 2 + (Y - x[1]) ** 2)
    X = g(X)
    Y = g(Y)
    R = g(R)
    print("{0:.3f} {1:.3f} {2:.3f}".format(X, Y, R))
n = int(input())
a = []
for _ in range(n):
    a.append(list((map(float, input().split()))))
for i in a:
    f(i)

Python: 
import sys
import math


def solv(x1, y1, x2, y2, x3, y3):
    if y2 == y1:
        xp = 0.5 * (x1 + x2)
        yp = (x3 - x1)/(y3 - y1) * xp + 0.5 * (y1 + y3 - (x3**2 - x1**2)/(y3 - y1))
    elif y3 == y1:
        xp = 0.5 * (x1 + x3)
        yp = (x2 - x1)/(y2 - y1) * xp + 0.5 * (y1 + y2 - (x2**2 - x1**2)/(y2 - y1))
    else:
        xp = 0.5 * (y3 - y2 - (x3**2 - x1**2)/(y3 - y1) + (x2**2 - x1**2)/(y2 - y1))/((x2 - x1)/(y2 - y1) - (x3 - x1)/(y3 - y1))
        yp = (x2 - x1)/(y2 - y1) * xp + 0.5 * (y1 + y2 - (x2**2 - x1**2)/(y2 - y1))
    r = math.sqrt((x1 - xp)**2 + (y1 - yp)**2)
    return (xp, yp, r)



#input_file = open(sys.argv[1], "r")
#lines = input_file.readlines()
lines = sys.stdin.readlines()
lines.pop(0)

for line in lines:
    l = map((lambda x: float(x)), line.split(' '))
    x1 = l[0]
    y1 = l[1]
    x2 = l[2]
    y2 = l[3]
    x3 = l[4]
    y3 = l[5]
    xp, yp, r = solv(x1, y1, x2, y2, x3, y3)
    print("%5.3f %5.3f %5.3f" % (xp, yp, r))

Python: for _ in[0]*int(input()):
 a,b,c,d,e,f=map(int,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-d)+(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:.4} {y:.4} {(x*x+y*y)**.5:.4}")

Python: n = int(input())
import math
for _ in range(n):
    ax,ay,bx,by,cx,cy = [float(i) for i in input().split()]
    ab = math.sqrt((ax-bx)**2+(ay-by)**2)
    bc = math.sqrt((bx-cx)**2+(by-cy)**2)
    ca = math.sqrt((cx-ax)**2+(cy-ay)**2)
    cos_a = (ab**2+ca**2-bc**2)/(2*ab*ca)
    sin_a = math.sqrt(1-cos_a**2)
    r = bc/(2*sin_a)
    px = ((ay-cy)*(ay**2 -by**2 +ax**2 -bx**2) -(ay-by)*(ay**2 -cy**2 +ax**2 -cx**2)) / (2*(ay-cy)*(ax-bx)-2*(ay-by)*(ax-cx))
    py = ((ax-cx)*(ax**2 -bx**2 +ay**2 -by**2) -(ax-bx)*(ax**2 -cx**2 +ay**2 -cy**2)) / (2*(ax-cx)*(ay-by)-2*(ax-bx)*(ay-cy))
    def round3(x):
        x_ = x*10**3
        if x_%1 < 0.5:
            x_ = math.floor(x_)
        else:
            x_ = math.ceil(x_)
        return x_*10**(-3)
        
            
    print("{:.3f} {:.3f} {:.3f}".format(round3(px),round3(py),round3(r)))

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.sqrt(px ** 2 + py ** 2)
    print("{0:.3f} {1:.3f} {2:.3f}".format(px, py, r))

Python: import math

def run():
    n = int(input())
    epsilon = 1e-16
    for _ in range(n):
        x1, y1, x2, y2, x3, y3 = list(map(float, input().split()))
        u1 = (x1-x3)*(x2-x1)*(x3-x2)
        u2 = (x2-x1)*(y3-y2)*(y3+y2)
        u3 = (x3-x2)*(y2-y1)*(y2+y1)
        v = x1*x2 + x2*y3 + x3*y1 - x1*y3 - x2*y1 + x3*y2
        Py = (-u1 + u2 - u3) / v / 2
        Px = (x2**2 - x1**2 + y2**2 - y1**2 - (y2 - y1)*Py) / (x2-x1 + epsilon) / 2
        r = math.sqrt((Px-x1)**2 + (Py-y1)**2)
        print('{0:.3f} {1:.3f} {2:.3f}'.format(round(Px,3), round(Py,3), round(r,3)))

if __name__ == '__main__':
    run()