import sys, math
sys.setrecursionlimit(1000000)
INF = 1 << 100
#mod = 1000000007
mod = 998244353
input = lambda: sys.stdin.readline().rstrip()
li = lambda: list(map(int, input().split()))

def f(v):
    a = L * 20 * u
    b = 20*u*T*v
    c = v**2
    return a > b + c

N = int(input())
out = []
for _ in range(N):
    T, u, L = map(float, input().split())
    ok = 10**7
    ng = 0
    while (ok - ng) > 0.00001:
        mid = (ok + ng) / 2
        if f(mid):
            ng = mid
        else:
            ok = mid
    ok *= 3.6
    out.append(ok)

for o in out:
    x = int(o * 100) / 100
    print('{:.2f}'.format(x))