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In coordinate geometry, three points could make a triangle, if the area of triangle is zero, It means the three points is collinear, else the points are non-collinear.

For example, Point A (x1,y1) = (1, 2), Point B (x2,y2) = (3, 5), Point C (x3,y3) = (4, 7).
Area = 1/2{ (x1 y2 + x2 y3 + x3 y1) - ( x2 y1 + x3 y2 + x1 y3) }
= 1/2{(5+21+8) - (6+20+7 )}
= 1/2(34 - 33)
= 1/2(1)
= 0.5
Area != 0; The given points are non collinear.