The statement given in the question, that if A,B, C are collinear then AB+BC= AC, will hold good only if B lies between A and C

The statement given in the question, that if A,B, C are collinear then AB+BC= AC, will hold good only if B lies between A and C. This is necessary for the Segment addition Postulate to be applicable.

The highlighted portion above, is the first half of the Segment addition Postulate, which is missing in the given statement of the question.

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