Answer:
Segment Addition Postulate
Step-by-step explanation:
In geometry, the Segment Addition Postulate states that given 2 points A and C(in this case S and O), a third point B(in this case R) lies on the line segment AC if and only if the distances between the points satisfy the equation AB + BC = AC.
Meaning for R to lie on the line SO;
SR + RO must be equal to SO
