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put this solution on YOUR website! 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
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