Question

s, u, n are collinear. select the point that satisfies the definition of betweenness if nu + us = ns.

Explanation:

Step1: Recall between - ness definition

If three points $A$, $B$, $C$ are collinear, then $B$ is between $A$ and $C$ if $AB + BC=AC$.

Step2: Identify points in given equation

Given $NU + US=NS$, comparing with the between - ness formula, we can see that $U$ is the point between $N$ and $S$.

Answer:

$U$