Question

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

Explanation:

Given that \( S \), \( U \), \( N \) are collinear and the equation \( NU + US = NS \). By the definition of betweenness of points, if a point \( U \) lies between \( N \) and \( S \), then the sum of the lengths of \( NU \) and \( US \) is equal to the length of \( NS \) (i.e., \( NU+US = NS \)). So the point that satisfies the definition of betweenness here is \( U \) as it lies between \( N \) and \( S \) to make the segment addition postulate hold.

Answer:

U