# Video: Identifying the Line of Reflection That a Known Triangle Is Reflected on to Gain Another Known Triangle

In which line must โณ๐น๐ท๐ฟ be reflected to map it onto โณ๐น๐ถ๐ฟ?

01:15

### Video Transcript

In which line must triangle ๐น๐ท๐ฟ be reflected to map it onto triangle ๐น๐ถ๐ฟ?

Letโs start by highlighting triangle ๐น๐ท๐ฟ and triangle ๐น๐ถ๐ฟ. Hereโs triangle ๐น๐ท๐ฟ. And hereโs triangle ๐น๐ถ๐ฟ. In a reflection, every point is the same distance from the central line. And the central line is the line that is being reflected over.

Our points ๐น and ๐ฟ are not changing. Point ๐ท turns into point ๐ถ. Point ๐ท and point ๐ถ are the same distance from the line ๐น๐ธ. ๐ถ is four units away from the line ๐น๐ธ. And ๐ท is four units away from the line ๐น๐ธ. Because points ๐น and ๐ฟ lie on the central line, they wonโt change.

Triangle ๐น๐ท๐ฟ can be reflected over line ๐น๐ธ to produce triangle ๐น๐ถ๐ฟ.