Question Video: Reflecting a Line Segment Where the Line of Reflection Is Horizontal Mathematics • First Year of Preparatory School

Video Transcript

Which of the following represents the image of the line segment 𝐴𝐵 after a reflection in the line 𝐿?

Remember, we can reflect a line segment through a line by reflecting its endpoints. When we do so, the image of each point will be the same perpendicular distance from the mirror line as the original point. So, let’s do this for each diagram. When we do so, we can see that options (B) and (C) are definitely incorrect. And at first glance, option (D) looks correct. But we can see that the vertices have been reversed. In fact, the correct answer is option (A). This represents the image of the line segment 𝐴𝐵 after a reflection in line 𝐿.