def area
      vec1 = vertices[1] - vertices[0]
      vec2 = vertices[2] - vertices[0]
      outer_product = vec1.cross(vec2)
      return outer_product.length / 2.0
    end
def area
      vec1 = vertices[1] - vertices[0]
      vec2 = vertices[2] - vertices[0]
      outer_product = vec1.cross(vec2)
      return outer_product.length / 2.0
    end
[Output]
  return area as Numeric.