Learning goals: Teacher Facing Generalize a process for identifying similar triangles and justify (orally) that finding two pairs of congruent angles is sufficient to show similarity. Justify (orally) that two triangles are similar by finding a sequence of transformations that takes one triangle to the other or checking that two pairs of corresponding angles are congruent. Full lesson plan (warm-up, activities, synthesis, cool-down prompt) from 8.2 Dilations, Similarity, and Introducing Slope, Grade 8.