Lesson 15
Reasoning About Angles (Part 2)
Lesson Purpose
Lesson Narrative
In this lesson, students use what they know about angles and their measurements to solve problems that are increasingly more complex and abstract. To find measurements of unknown angles, students need to look for structure in the diagrams, reason about the relationships of the angles (including writing equations to represent the relationships), and perform addition, subtraction, and sometimes division.
The problems in the lesson can be solved in more than one way and in different orders, but a small handful of the angles can only be quantified after the values of some other angles are known. Students pay attention to the process and explain why sometimes a certain sequence is necessary.
- Representation
- MLR8
Learning Goals
Teacher Facing
- Represent angle relationships and solve for unknown angle measurements.
Student Facing
- Let’s figure out missing angle measurements.
Required Materials
Materials to Copy
- Info Gap: Whole Bunch of Angles
Required Preparation
Activity 2:
- Create a set of cards from the blackline master for each group of 2.
Lesson Timeline
Warm-up | 10 min |
Activity 1 | 15 min |
Activity 2 | 20 min |
Lesson Synthesis | 10 min |
Cool-down | 5 min |
Teacher Reflection Questions
Suggested Centers
- Which One? (K–5), Stage 4: Grade 3 Shapes (Supporting)
- Can You Draw It? (1–5), Stage 4: Area and Perimeter (Supporting)
Print Formatted Materials
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Student Task Statements | docx | |
Lesson Cover Page | docx | |
Cool Down | Log In | |
Teacher Guide | Log In | |
Teacher Presentation Materials | docx | |
Blackline Masters | zip |