This lesson unit is intended to help you assess how students reason about geometry and, in particular, how well they are able to: use facts about the angle sum and exterior angles of triangles to calculate missing angles; apply angle theorems to parallel lines cut by a transversal; interpret geometrical diagrams using mathematical properties to identify similarity of triangles.

Students will learn about the reflective behaviors of light, and the wave and particle nature of light. Students will also recognize congruency of angles.

In this lesson, students know that corresponding angles, alternate interior angles, and alternate exterior angles of parallel lines are equal. Students know that when these pairs of angles are equal, then lines are parallel. Students know that corresponding angles of parallel lines are equal because of properties related to translation. Students know that alternate interior angles of parallel lines are equal because of properties related to rotation. Students present informal arguments to draw conclusions about angles formed when parallel lines are cut by a transversal.

This course was created by the Rethink Education Content Development Team in partnership with the North Carolina Virtual Public Schools. This course is aligned to the NC Standards for 8th Grade Math. 

This course was created by the Rethink Education Content Development Team in partnership with the North Carolina Virtual Public Schools. This course is aligned to the NC Standards for 8th Grade Math. 

This course was created by the Rethink Education Content Development Team in partnership with the North Carolina Virtual Public Schools. This course is aligned to the NC Standards for 8th Grade Math. 

In this lesson, students know a third informal proof of the angle sum theorem. Students know how to find missing interior and exterior angle measures of triangles and present informal arguments to prove their answer is correct.

ile patterns will be familiar with students both from working with geometry tiles and from the many tiles they encounter in the world. Here one of the most important examples of a tiling, with regular hexagons, is studied in detail. This provides students an opportunity to use what they know about the sum of the angles in a triangle and also the sum of angles which make a line.

This task aims at explaining why four regular octagons can be placed around a central square, applying student knowledge of triangles and sums of angles in both triangles and more general polygons.