Lesson 6

The purpose of this lesson is for students to consider ways to compare angles and describe the size of angles.

In previous lessons, students identified and described lines, line segments, rays, and angles in geometric and real-world contexts. The purpose of the exploratory work in this lesson is for students to make sense of which attributes define an angle (rays at a common endpoint) and which attributes do not (length of the line segments). The activities in the lesson intentionally elicit students’ ideas for how to describe an angle’s size.

Throughout the lesson, monitor for the ways students distinguish visible line segments from the rays that compose the angles and the language they use to describe the size of angles.

• Create one set of cards from the blackline master for each group of 2 students.

In today’s lesson, students had the opportunity to compare angles using the language that makes sense to them. What language did they use to describe the size of angles? How can you build on this language in the next lesson when the size of an angle is described as a turn from one ray from the other?