n=int(input())
for _ in range(n):
  t,m,l=map(float,input().split())
  t=int(t*100)
  m=int(m*100)
  l=int(l*100)
  ok=0
  ng=10**7
  while ng-ok>1:
    v=(ok+ng)//2
    if 2*m*v*t*36+v*10*v*10<=20*m*l*36*36:
      ok=v
    else:
      ng=v
  v=ok
  v=str(v).zfill(6)
  v1,v2=v[:4],v[4:]
  print(str(int(v1))+"."+v2.zfill(2))