import sys
#input = sys.stdin.readline
input = sys.stdin.buffer.readline #文字列はダメ
#sys.setrecursionlimit(1000000)
#import bisect
#import itertools
#import random
#from heapq import heapify, heappop, heappush
#from collections import defaultdict 
#from collections import deque
#import copy
#import math
#from functools import lru_cache
#@lru_cache(maxsize=None)
MOD = pow(10,9) + 7
#MOD = 998244353
#dx = [1,0,-1,0]
#dy = [0,1,0,-1]
#dx8 = [1,1,0,-1,-1,-1,0,1]
#dy8 = [0,1,1,1,0,-1,-1,-1]

def hantei(x,T,m,L):
    # val = v**2 + 20*m*T*v - 20*m*L
    val = x**2 + 7200*m*T*x - 20*360*360*m*L
    return val <= 0


def main():
    N = int(input())
    for _ in range(N):
        T,m,L = map(float,input().split())
        # xの最大値と最小値。答えはこれを100で割る
        ng = pow(10,9)
        ok = 0
        while abs(ok-ng) > 1:
            mid = (ok+ng)//2
            if hantei(mid,T,m,L):
                ok = mid
            else:
                ng = mid
        ok = str(ok)
        if len(ok) == 1:
            ans = '0.0' + str(ok)
        elif len(ok) == 2:
            ans = '0.' + str(ok)
        else:
            ans = ok[:-2] + '.' + ok[-2:]
        print(ans)




if __name__ == '__main__':
    main()