import sys
import pypyjit
import itertools
import heapq
import math
from collections import deque, defaultdict
import bisect
from decimal import Decimal, ROUND_DOWN

input = sys.stdin.readline
sys.setrecursionlimit(10 ** 6)
pypyjit.set_param('max_unroll_recursion=-1')


def index_lt(a, x):
    'return largest index s.t. A[i] < x or -1 if it does not exist'
    return bisect.bisect_left(a, x) - 1


def index_le(a, x):
    'return largest index s.t. A[i] <= x or -1 if it does not exist'
    return bisect.bisect_right(a, x) - 1


def index_gt(a, x):
    'return smallest index s.t. A[i] > x or len(a) if it does not exist'
    return bisect.bisect_right(a, x)


def index_ge(a, x):
    'return smallest index s.t. A[i] >= x or len(a) if it does not exist'
    return bisect.bisect_left(a, x)


def S(v, t, m):
    v = v * 1000 / 3600
    return v * t + (v * v) / (20 * m)


N = int(input())
for _ in range(N):
    T, m, L = map(float, input().split())

    l = 0
    r = 5100
    while r - l > 10 ** (-6):
        c = (l + r) / 2
        if S(c, T, m) <= L:
            l = c
        else:
            r = c
    print(Decimal(str(r)).quantize(Decimal('0.01'), rounding=ROUND_DOWN))