> [!summary] Two triangles are similar if they share one of the following properties: > - Side lengths are proportional > - All angles are identical to one another >[!info]+ Read Time **⏱ 1 min** # Definition Triangles are similar if their side lengths are proportional or if all angles are the same. For example, looking at the image below, $\triangle ABC$ and $\triangle EDF$ are similar because all their angles are identical. If their angles weren't identical but all the lengths were proportional to one another, they would also be similar. ![[st_1.png]] # Resources <iframe width="560" height="315" src="https://www.youtube.com/embed/mJ4Ms6SXEgg?si=s3xFzo3cRD2hfxEI" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe> --- > 📂 Want to see more structured notes like these? > Help grow the project by [starring Math & Matter on GitHub](https://github.com/rajeevphysics/Obsidian-MathMatter). ---