Final answer:
The Segment Addition Postulate states that if point B lies on line segment AC, then AB + BC = AC, but the exact label (Postulate 1, 2, 3, or 4) is not provided.
Step-by-step explanation:
The mathematical postulate that states if point B lies on line segment AC, then AB + BC = AC is known as the Segment Addition Postulate. Unfortunately, without additional context, it is unclear which of the provided options (Postulate 1, 2, 3, or 4) corresponds to the Segment Addition Postulate, as these labels can vary depending on the textbook or curriculum. However, the essence of the postulate remains that the total length of a line segment is equal to the sum of the lengths of its parts.The mathematical postulate that states if point B lies on line segment AC, then AB + BC = AC is Postulate 1. In other words, the sum of the lengths of the two parts of a line segment is equal to the length of the whole line segment. This postulate is also known as the Segment Addition Postulate. For example, if AB is 3 units long and BC is 4 units long, then AC must be 7 units long.