n = int(input())
for _ in range(n):
    b, a, c = map(float, input().split())
    v = 2 * (5 ** .5 * (a * (5 * a * b ** 2 + c)) ** .5 - 5 * a * b)
    x, y = str(v * 3600 / 1000).split('.')
    print(x, y[:2][::-1].zfill(2)[::-1], sep='.')