8.G.A.5
Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles.
Cluster 8.G.AUnderstand congruence and similarity using physical models, transparencies, or geometry software.
Where this sits in the school year
Our Grade 8 Math scope and sequence teaches 8.G.A.5 in Unit 2: Dilations, Similarity & Angles, weeks 4–6.
Add dilations to build similarity, and establish the angle facts that make the angle-angle criterion work. See the full pacing guide →
Builds on
Suggested prerequisites. This sequencing is our editorial guidance, not part of the Common Core.
Teaching Kits for this standard
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