Education Technology

Geometry: Nested Similar Triangles
by Texas Instruments

Published on August 28, 2011


  • Students will be able to identify the conditions that determine when nested triangles that share a common angle are similar triangles.
  • Students will validate conditional statements about nested triangles that share a common angle.


  • similar polygons
  • corresponding parts
  • parallel
  • nested triangles

About the Lesson

In this lesson, nested triangles have been created so that they share a common vertex and vertex angle. The students will drag the endpoints of the side that is opposite the common angle to discover the conditions that make the nested triangles similar. When students make congruent angle marks appear, the triangles will be similar.