1.
import java.util.Scanner;

/**
 * FWP, Ausgewählte Probleme aus dem ACM Programming Contest, SS10 
 * Problem: 10991 - Region
 * Link: http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=226&page=show_problem&problem=1932
 * 
 * @author Siegfried Ippisch
 * @author Martin Lambeck
 * @version 1.0
 * 
 * Method : -
 * Status : Accepted
 * Runtime: 0.864
 */
public class Region {
	
	static Scanner in = new Scanner(System.in);
	
	public static void main (String...s)
	{
		int c = in.nextInt();
		
		for (int i = 0; i < c; i++)
			testcase();
	}
	
	static void testcase()
	{
		
		// Radien
		double ra = in.nextDouble();
		double rb = in.nextDouble();
		double rc = in.nextDouble();
		
		// Winkel
		double a = angle(ra+rb, ra+rc, rb+rc);
		double b = angle(rb+rc, ra+rb, ra+rc);
		double c = angle(ra+rc, rb+rc, ra+rb);
		
		// Test
		if (Math.abs(a+b+c -Math.PI) > 0.0001)
			throw new NullPointerException();
		
		// Fläche berechnen
		double triarea = triarea(ra+rb, ra+rc, rb+rc);
		triarea -= (ra*ra) * 0.5 * a;
		triarea -= (rb*rb) * 0.5 * b;
		triarea -= (rc*rc) * 0.5 * c;
		
		System.out.printf("%.6f%n", triarea);
		
	}
	
	/**
	 * Winkel, im Dreieck, mit Cosinussatz berechnen
	 * @param a,b,c Seiten
	 * @return Winkel gegenüber von c
	 */
	static double angle(double a, double b, double c)
	{
		return Math.acos((c*c - a*a - b*b) / (-2 * a * b));
	}
	
	/**
	 * Dreiecksfläche berechnen
	 * @param a,b,c Seiten
	 * @return Fläche
	 */
	static double triarea(double a, double b, double c)
	{
		double s =(a+b+c)/2.0;
		
		double f = Math.sqrt(s*(s-a)*(s-b)*(s-c));
		
		return f ;
	}

}