Question

what is the fourth reason? segment addition postulate definition of midpoint given substitution property

Explanation:

The Segment Addition Postulate states that if we have a line - segment AC and a point B on it, then AB + BC=AC. If B is the mid - point of AC (given), AB = BC. When we substitute BC with AB in the equation AB + BC = AC to get AB+AB = AC (or 2AB = AC), we are using the Substitution Property.

Answer:

Substitution Property