# Angles of a Triangle: Triangles in the Trees

This is one lesson in a larger Unit Plan that covers many properties of triangles and several other theorems. It has proofs, real world problems, constructions, a unit project, assessments, and more. In Lesson 9, “Triangles in the Trees (Angles of a Triangle)”, students investigate the Triangle Sum Theorem, Triangle Inequality Theorem, and Exterior Angle Theorem. One of the activities is a hands-on activity. Includes lesson plan, and a variety of downloadable student handouts (with and without Geometer's Sketchpad instructions). The entire unit plan can be found here. The Lesson investigates Triangle Sum Theorem with a hands-on activity. The Triangle Inequality Theorem is discovered through a drawing activity, as is Exterior Angle Theorem. There are also several real world connections.

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