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: #!/usr/bin/env 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 = "{0:.3f}".format(g(X))
	Y = "{0:.3f}".format(g(Y))
	R = "{0:.3f}".format(g(R))
	if X == "-0.000" or Y == "-0.000" or R == "-0.000":
		while True:
			X += 0
	print(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
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 + (p-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] = x2**2 + y2**2 - x1**2 - y1**2
		w[3] = 2*(x3-x1)
		w[4] = 2*(y3-y1)
		w[5] = x3**2 + y3**2 - x1**2 - y1**2

		x, y = solve(w)

		r = math.sqrt((x-x1)**2 + (y-y1)**2)

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

Python: for _ in range(int(input())):
    a,d,b,e,c,f=map(float,input().split())
    z=2*(b*f-c*e+c*d-a*f+a*e-b*d)
    x=((e-f)*(a**2+d**2)+(f-d)*(b**2+e**2)+(d-e)*(c**2+f**2))/z
    y=((c-b)*(a**2+d**2)+(a-c)*(b**2+e**2)+(b-a)*(c**2+f**2))/z
    print('{0:.3f} {1:.3f} {2:.3f}'.format(x,y,((a-x)**2+(d-y)**2)**0.5))

Python: import math
for _ in range(int(input())):
    x1, y1, x2, y2, x3, y3 = map(float, input().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)-(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)-(x1-x2)*(y1-y3))
    r = math.sqrt((x1 - p) ** 2 + (y1 - q) ** 2)
    print("{:.3f} {:.3f} {:.3f}".format(p, q, r))

Python: from math import sin,cos,sqrt
n=int(input())
out=[]
for i in range(n):
	I=list(map(float,input().split(" ")))
	#( (x_0,y_0), (x_1,y_1) , (x_2,y_2) )
	a_1=I[2]-I[0] #x_1-x_0
	a_2=I[4]-I[0] #x_2-x_0
	b_1=I[3]-I[1] #y_1-y_0
	b_2=I[5]-I[1] #y_2-y_0
	#print(a_1,b_1,a_2,b_2)

	K=(a_2**2 -a_2*b_2+a_1**2-a_1*b_1)/(a_2*b_1-a_1*b_2)

	O_x=0.5*(b_1-K*b_2)
	O_y=0.5*(b_2+K*b_1)
	O_R=sqrt( (I[0]-O_x)**2  + (I[1]-O_y)**2 )

	out.append( '{:.3f} {:.3f} {:.3f}'.format(O_x,O_y,O_R) )



for i in out:
	print(i)

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 math
n=int(input())
for i in range(n):
    x1,y1,x2,y2,x3,y3=[float(i) for i in input().split()]
    t1=x1*(x2+x3-x1)+y1*(y2+y3-y1)
    t2=x2*(x1+x3-x2)+y2*(y1+y3-y2)
    t3=x3*(x1+x2-x3)+y3*(y1+y2-y3)
    px=(t1*x1+t2*x2+t3*x3)/(t1+t2+t3)
    py=(t1*y1+t2*y2+t3*y3)/(t1+t2+t3)
    r=math.hypot(px-x1,py-y1)
    print("{0} {1} {2}".format(round(px,3),round(py,3),round(r,3)))