from math import sqrt,floor

N = int(input())
for _ in range(N):
	T, m, L = map(float, input().split())
	ans = -10 * m * T + sqrt((10*m*T)**2 + 20*m*L)
	ans = ans * 0.001 * 3600
	n = 5
	ans = floor(ans * 10 ** n) / (10 ** n)
	i = str(ans).find('.')
	if len(str(ans)) - i == 2:
		print(str(ans) + '0')
	elif len(str(ans)) - i == 1:
		print(str(ans) + '00')
	else:
		print(str(ans)[:i+3])