https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-triangle-similarity-intro/v/similar-triangle-basics 2021-02-16T16:08:13Z Intro to triangle similarity Sal explains what it means for triangles to be similar, and how this follows from the definition of similarity. Sal Khan video https://cdn.kastatic.org/googleusercontent/OHhtWwIKWzAma1-dD917cycApEdcQ-aA6xy51bFuRX0N3nbYSM7_3kEBAv3uEJgntUvnRdTG8APh1fygBYK9Pfc Intro to triangle similarity Sal explains what it means for triangles to be similar, and how this follows from the definition of similarity. https://cdn.kastatic.org/ka-youtube-converted/9ThXDY9Y3oU.mp4/9ThXDY9Y3oU.mp4 557 Similarity https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-triangle-similarity-intro/a/triangle-similarity-review 2026-03-26T05:20:35.16058035Z Triangle similarity review Review the triangle similarity criteria and use them to determine similar triangles. article https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-triangle-similarity-intro/e/similar_triangles_1 2025-12-28T12:11:43.202987517Z Determine similar triangles: Angles Given two triangles with some of their angle measures, determine whether the triangles are similar or not. Igor Terzic exercise https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-triangle-similarity-intro/e/similar_triangles_2 2025-12-28T12:11:43.202987517Z Determine similar triangles: SSS Given two triangles with their side measures, determine whether the triangles are similar or not. Matt Wahl exercise https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-solving-similar-triangles/v/similarity-example-problems 2021-02-16T16:08:13Z Solving similar triangles Sal solves two problems where a missing side length is found by proving that triangles are similar and using this to find the measure. Sal Khan video https://cdn.kastatic.org/googleusercontent/uBaXzPQK4hkXk7SLRWcXexNEC9Lk0L9CFM72JdwRPDmK1zGvKp402QwUYo4Na3EUXaw_9PfwGBEj9Qrdln3ikuc Solving similar triangles Sal solves two problems where a missing side length is found by proving that triangles are similar and using this to find the measure. https://cdn.kastatic.org/ka-youtube-converted/R-6CAr_zEEk.mp4/R-6CAr_zEEk.mp4 457 Similarity https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-solving-similar-triangles/e/solving_similar_triangles_1 2026-03-24T23:41:07.080866137Z Solve similar triangles (basic) Given two similar triangles and some of their side lengths, find a missing side length. Matt Wahl exercise https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-solving-similar-triangles/v/similarity-example-where-same-side-plays-different-roles 2021-02-16T16:08:12Z Solving similar triangles: same side plays different roles Sal finds a missing side length in a problem where the same side plays different roles in two similar triangles. Sal Khan video https://cdn.kastatic.org/googleusercontent/lX9RMdkffZEOJGNNNrVBHvaPeKUUPVlUHER8W4HSB9702VE6rsZRk5vxPUX9VVNB0ye6q-28CsXa9owU6G6ulLQJ Solving similar triangles: same side plays different roles Sal finds a missing side length in a problem where the same side plays different roles in two similar triangles. https://cdn.kastatic.org/ka-youtube-converted/Tal_fgREll0.mp4/Tal_fgREll0.mp4 365 Similarity https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-solving-similar-triangles/e/solving_similar_triangles_2 2026-02-25T07:10:43.942529673Z Solve similar right triangles Find missing side lengths in figures composed of similar right triangles. Jon Hoye exercise https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-triangle-similarity-intro/v/similar-triangle-example-problems 2021-02-16T16:08:13Z Determining similar triangles Multiple examples where Sal analyzes the similarity of triangles. Sal Khan video https://cdn.kastatic.org/googleusercontent/wPNNkYb835QjARVtFnJEJ7MMR046Ell7tM3CRf9VJflgBgxUyU5OjB93c3fwEWM8bgX8WcA4_USbRi1QYzR0-l0c Determining similar triangles Multiple examples where Sal analyzes the similarity of triangles. https://cdn.kastatic.org/ka-youtube-converted/Ly86lwq_2gc.mp4/Ly86lwq_2gc.mp4 563 Similarity https://www.khanacademy.org/math/revision-term-1-mh-math-class-10/x041ca11815640a3a:week-1/x041ca11815640a3a:similarity/e/basic-proportionality-theorem-problems 2025-12-30T07:05:15.972746521Z Basic proportionality theorem problems The exercise tests how students can identify missing lengths by applying basic proportionality theorem and its converse Devashish Phadnis exercise https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-similarity-definitions/v/testing-similarity-through-transformations 2023-05-12T21:01:01.897246564Z Similar shapes & transformations Two shapes are similar if we can change one shape into the other using rigid transformations (like moving or rotating) and dilations (making it bigger or smaller). Other kinds of transformations can change the angles or the ratios of lengths in a figure. If we need those types of transformations, the shapes are not similar. Sal Khan video https://cdn.kastatic.org/ka_thumbnails_cache/95165e7e-8131-4ac8-a2d0-7ee788f53bf6_1280_720_base.png Similar shapes & transformations Two shapes are similar if we can change one shape into the other using rigid transformations (like moving or rotating) and dilations (making it bigger or smaller). Other kinds of transformations can change the angles or the ratios of lengths in a figure. If we need those types of transformations, the shapes are not similar. https://cdn.kastatic.org/ka-youtube-converted/H-YuW_uckz4.mp4/H-YuW_uckz4.mp4 158 Similarity https://www.khanacademy.org/math/geometry/hs-geo-similarity/hs-geo-similarity-definitions/e/exploring-angle-preserving-transformations-and-similarity 2026-03-09T04:30:46.094426574Z Similarity & transformations Given a pair of figures in the coordinate plane, determine whether they are similar based on whether it is possible to map one to the other using angle-preserving transformations. Tomer Gal exercise