from math import sqrt,floor

N = int(input())
for _ in range(N):
	T, m, L = map(float, input().split())
	ans = -10 * m * T + sqrt(100*m*m*T*T + 20*m*L)
	ans = floor(ans * 0.001 * 3600 * 100)/100
	print(format(ans,'.2f'))