Cannon#428
A cannon is placed at the origin and shoots ping-pong balls. At a distance from it, parallel to the axis, there is an infinitely long brick wall. Between the wall and the axis, there is a point target at coordinates (X, Y). Adjust the cannon's aim so that the ball first bounces off the wall and then hits the target. Determine the shortest distance from the axis to the point where the ball collides with the wall.
The first line contains the number of tests.
For each test, a separate line contains three integers , , and (-10 \leq X \leq 10, 0 \leq Y < R \leq 10), separated by spaces.
For each test, output on a separate line the distance along a straight line from the axis to the point where the ball hits the wall, rounded to two decimal places.
Example 1