Question 88376
  Hi how can i find the area of a triangle using a determinant and the following vertices; (1,-9), (-9, -2), (-7,6)
Area of the triangle whose vertices are (x1,y1)(x2,y2) &(x3,y3)is given by
   A = x1  y1  1
        x2  y2  1 divided by 2   [Determinant]
        x3  y3  1

      1  -9   1    [Determinant]
     -9  -2   1
     -7   6   1   Area of triangle = 1/2.[1(-2-6)-(-9)(-9+7)+1(-54-14)] 
                                   = 1/2.[-8-18-68]
                                   = 1/2.(-94)
                                   = -47
    Taking the absolute value of the area we get Area of the triangle = 47 sq units