require "matrix"

def line_length(x1, y1, x2, y2)
  if x1 == x2
    (y1 - y2).abs
  elsif y1 == y2
    (x1 - x2).abs
  else
    Math.sqrt((x2-x1)**2 + (y2-y1)**2)
  end
end

gets
ARGF.each do |line|
  x1,y1,x2,y2,x3,y3 = line.split.map(&:to_f)
  l1 = line_length(x1, y1, x2, y2)
  l2 = line_length(x1, y1, x3, y3)
  l3 = line_length(x2, y2, x3, y3)
  r = (l2 / Math.sin( Vector[x1-x2, y1-y2].angle_with(Vector[x2-x3,y2-x3]) )) / 2
  puts r
end