AOJ0010

0010.cpp

#include <cmath>
#include <cstdio>
#include <iostream>
#include <iomanip>
#include <stack>
#include <list>
#include <vector>

using namespace std;

int main(void) {
    int num;
    double x[3], y[3], a1, a2, b1, b2, c1, c2, px, py, r;

    cin >> num;

    for(int i = 0; i < num; i++) {
	cin >> x[0] >> y[0] >> x[1] >> y[1] >> x[2] >> y[2];

	a1 = 2*(x[1]-x[0]);
	b1 = 2*(y[1]-y[0]);
	c1 = (x[0]*x[0] - x[1]*x[1]) + (y[0]*y[0] - y[1]*y[1]);
	a2 = 2*(x[2]-x[0]);
	b2 = 2*(y[2]-y[0]);
	c2 = (x[0]*x[0] - x[2]*x[2]) + (y[0]*y[0] - y[2]*y[2]);

	px = (b1*c2-b2*c1)/(a1*b2-a2*b1);
	py = (c1*a2-c2*a1)/(a1*b2-a2*b1);
	r = sqrt(pow(px-x[0],2)+pow(py-y[0],2));

	cout << fixed << setprecision(3) << px << " " << py << " " << r << endl;

    }

    return 0;
}