/**

* Umm! So, you claim yourself as an intelligent one? Let me check. As, computer science students always

* insist on optimization whenever possible, I give you an elementary problem of math to optimize.

* You are trying to cross a river of width d meters. You are given that, the river flows at v ms−1 and

* you know that you can speed up the boat in u ms−1

* . There may be two goals how to cross the river:

* One goal (called fastest path) is to cross it in fastest time, and it does not matter how far the flow of

* the river takes the boat. The other goal (called shortest path) is to steer the boat in a direction so that

* the flow of the river doesn’t take the boat away, and the boat passes the river in a line perpendicular to

* the boarder of the river. Is it always possible to have two different paths, one to pass at shortest time

* and the other at shortest path? If possible then, what is the difference (Let P s) between the times

* needed to cross the river in the different ways?

* Input

* The first line in the input file is an integer representing the number of test cases. Each of the test cases

* follows below. Each case consists three real numbers (all are nonnegative, d is positive) denoting the

* value of d, v and u respectively.

* Output

* For each test case, first print the serial number of the case, a colon, an space and then print ‘can’t

* determine’ (without the quotes) if it is not possible to find different paths as stated above, else print

* the value of P corrected to three digits after decimal point. Check the sample input & output.

* Sample Input

* 3

* 8 5 6

* 1 2 3

* 1 5 6

* Sample Output

* Case 1: 1.079

* Case 2: 0.114

* Case 3: 0.135

*/

//https://uva.onlinejudge.org/index.php?option=onlinejudge&Itemid=99999999&page=show_problem&category=&problem=1714

import java.text.DecimalFormat;

import java.util.Scanner;

public class BackToIntermediateMath {

public static void main(String[] args) {

Scanner input = new Scanner(System.in);

int numberOfTestCases = input.nextInt();

DecimalFormat formatter = new DecimalFormat("#0.000");

for (int i = 0; i < numberOfTestCases; i++) {

double distance = input.nextDouble();

double riverSpeed = input.nextDouble();

double boatSpeed = input.nextDouble();

if (riverSpeed == 0 || boatSpeed == 0 || boatSpeed <= riverSpeed) {

System.out.println("Case " + (i + 1) + ": can't determine");

} else {

double P1 = distance / boatSpeed;

double P2 = distance

/ Math.sqrt(boatSpeed * boatSpeed - riverSpeed

* riverSpeed);

System.out.print("Case " + (i + 1) + ": "

+ formatter.format(Math.abs(P1 - P2)) + "\n");

}

}

}

}