import Control.Applicative
import Control.Monad
import Data.List.Split (chunksOf)
import Text.Printf

main :: IO ()
main = do
  getLine
  solve <$> chunksOf 7 <$> map (map read <$> words) <$> lines <$> getContents >>= mapM_ (printf "%f\n")

solve :: [[[Double]]] -> [Double]
solve = map f
  where
    f = minimum . filter (> 0) . map ang . filter (\[x, y] -> x < 0 && y > 0) . tail

ang :: [Double] -> Double
ang [x, _] = 180.0 * acos x / pi - 120.0