Unit 1, Lesson 3
There’s an Inequality Describing Any Triangle’s Sides
Integrated Math 2
Preparation
Lesson Narrative
In this lesson, students are completing part of the proof cycle. They are not yet writing formal proofs, but they attend to precision (MP6) as they use inequalities to formalize their understanding of and informally justify the Triangle Inequality Theorem. Then students have a chance to use their understanding of triangles to model the path of a ladybug (MP4). Students do not complete a full modeling cycle, but they are asked to decide what quantities are important and choose a mathematical representation that matches a simplified situation.
- Justify (orally and in writing) the Triangle Inequality Theorem.
- Use the Triangle Inequality Theorem to model and solve problems about triangles.