N = int(input())
def isok(v,T,u,L):
    if 25 * (v ** 2)  +18 * u*T*v -20 * u * L * (18 ** 2) <= 0:
        return True
    else:
        return False
def solve(T,u,L):
    ok = 0
    ng = 5400 * 10 ** 2
    while ng -ok > 1:
        v = (ng+ok) //2
        if isok(v,T,u,L):
            ok = v
        else:
            ng = v
    v = ok / 10 ** 2
    return v

ANS = []
for _ in range(N):
    T,u,L = map(lambda x:int(float(x)*10 ** 2),input().split())
    ANS.append(solve(T,u,L))
for ans in ANS:
    print('{:.2f}'.format(ans))