#! /usr/bin/env python
#
def triangle_area ( xa, ya, xb, yb, xc, yc ):

#*****************************************************************************80
#
## TRIANGLE_AREA computes the signed area of a triangle.
#
#  Licensing:
#
#    This code is distributed under the GNU LGPL license.
#
#  Modified:
#
#    17 October 2015
#
#  Author:
#
#    John Burkardt
#
#  Parameters:
#
#    Input, real XA, YA, XB, YB, XC, YC, the vertices.
#
#    Output, real AREA, the signed area of the triangle.
#
  area = 0.5 * ( ( xb - xa ) * ( yc - ya ) \
               - ( xc - xa ) * ( yb - ya ) )

  return area