Question

Given three collinear points, pt A, pt B, and pt C. Point B is between pt A and pt C. If AC=20 and BC=18, What theorem or postulate or definition allows me to find AB? (I need the theorem/postulate/definition name)

A) Midpoint Theorem
B) Segment Addition Postulate
C) Angle Bisector Theorem
D) Pythagorean Theorem

Answer 1

The Segment Addition Postulate allows you to find AB by subtracting the length of BC from the length of AC.

Step-by-step explanation:

The theorem or postulate or definition that allows you to find AB is the Segment Addition Postulate (Option B). According to the Segment Addition Postulate, if points B, A, and C are collinear with B between A and C, then the length of segment AB plus the length of segment BC is equal to the length of segment AC. Therefore, AB can be found by subtracting the length of BC (18) from the length of AC (20): AB = AC - BC = 20 - 18 = 2.