N = int(input())
for _ in range(N):
    T, mu, L = map(float,input().split())
    v = ((10*mu*T)**2 + 20*mu*L)**(1/2) - 10*mu*T
    u = int(v*3600/1000*100)
    print(u//100, '.', (u%100)//10, u%10, sep='')