CKMath Unit 7: Angles and Angle Measurement
Focus:
In this unit, students deepen and refine students’ understanding of geometric figures and measurement. In earlier grades, students learned about two-dimensional shapes and their attributes, which they described informally early on but with increasing precision over time. Here, students formalize their intuitive knowledge about geometric features and draw them. They identify and define some building blocks of geometry (points, lines, rays, and line segments), and develop concepts and language to more precisely describe and reason about other geometric figures. Students analyze cases where lines intersect and where they don’t, as in the case of parallel lines. They learn that an angle as a figure composed of two rays that share an endpoint. Later, students compare the size of angles and consider ways to quantify it. They learn that angles can be measured in terms of the amount of turn one ray makes relative to another ray that shares the same vertex. Students come to see that a 1-degree angle is 1/360 of a full turn or full circle and can be used to measure angles. They use a protractor to measure angles in whole-number degrees. Students also learn that angles are additive. When an angle is composed of multiple non-overlapping parts, the measure of the whole is the sum of the angle measures of the parts. These insights enable students to classify angles (as acute, obtuse, right, or straight) and to solve problems about missing angle measurements in concrete and abstract contexts.
Number of Lessons: 15 and 1 optional
Instruction Time:
Approximately 60 minutes
(Please note that each lesson is designed for one instructional block, and may be divided into shorter or longer segments based on teacher pacing and student needs.)
