mod = 998244353


def main():
    import sys
    import math
    input = sys.stdin.readline

    for _ in range(int(input())):
        t, m, l = map(float, input().split())
        ok = 0
        ng = 5101
        mid = (ok + ng) / 2
        while ng - ok > 10 ** -4:
            v = mid / 3.6
            if v * t + (v ** 2 / (20 * m)) >= l:
                ng = mid
            else:
                ok = mid
            mid = (ok + ng) / 2
        ans = str(math.floor((ok + 10 ** -4) * 100) / 100)
        if ans[-2] == ".":
            ans += "0"
        print(ans)


if __name__ == '__main__':
    main()