In this lesson, students revisit the process of geometric proof they learned in a previous course by learning how to write strong, clear conjectures. Students compare examples of side lengths that do and do not form a triangle and find patterns to generalize (MP8) their conceptual understanding of the Triangle Inequality Theorem. During a partner activity, students explain their thinking and listen to the reasoning of others (MP3).

Math Community
This is the first exercise that focuses on the work of building a mathematical community. Students have the opportunity to think about what a mathematical community is and to share their initial thoughts about what it looks like and sounds like to do math together in a community.