The formula for the area is

A = | x1*y2 + x2*y3 + x3*y1 - x1*y3 - x2*y1 - x3*y2 | / 2

If the xi and yi are integers, A is of the form (integer/2)

The formula for the area is

A = | x1*y2 + x2*y3 + x3*y1 - x1*y3 - x2*y1 - x3*y2 | / 2

If the xi and yi are integers, A is of the form (integer/2)

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