Mathematics ACT Aspire Practice Test – Math Prep, Free Practice Exam, Study Guide

A ray is defined as a part of a line that has one endpoint and extends indefinitely in one direction. This means that it starts from a specific point, known as the endpoint, and continues infinitely without ending on the other side. This definition captures the essential characteristics of a ray, distinguishing it from other geometric figures.

To provide context, a line is typically described as having no endpoints and extends infinitely in both directions, which is why that definition does not apply to a ray. A line segment, on the other hand, has two endpoints, thus differentiating it from the concept of a ray. The description of a plane refers to a flat surface, which again is not relevant to the definition of a ray, and a point is defined as a specific location without any dimensions, which also does not align with the characteristics of a ray. Therefore, the correct definition clearly stands out as focusing on the single endpoint and the infinite extension characteristic of a ray.