Unit 8, Lesson 10
Ways to Find Angle Measurements (Optional)
Grade 4
Preparation
Lesson Narrative
Previously, students analyzed the attributes of two-dimensional figures and used them to find side lengths and perimeters. In this lesson, students use the attributes of figures to find unknown angle measurements and to practice drawing line-symmetric figures. Both activities in the lesson deepen students’ understanding of line symmetry. The activities also allow students to apply knowledge of angles from an earlier unit and integrate it with newer ideas from this unit. Because the work here is not required by the standards, this lesson is optional.
- Representation
- MLR8
- Explain (orally) strategies for determining an unknown angle measurement using the attributes of two-dimensional figures.
- Let’s find angle measurements in figures with line symmetry.
Required Materials
Required Preparation
None
Extend the Launch of the Warm-up by engaging students in a discussion about the night sky. Ask:
- “What do you notice about the stars in the night sky?” (They seem far away. Some are bigger and brighter than others. They form patterns. They look like they move in the sky.)
- “Why is it easier to see stars in some places than in others?” (Stars are hard to see where there are clouds in the sky, in places where there is smog or other types of air pollution, and where there are other lights, such as from homes, skyscrapers, and streetlamps.)
Explain that in most cities and suburbs, it’s hard to see stars because of light pollution, the overuse of human-made light. Light pollution can confuse wildlife and keep people awake at night. It wastes energy, and makes it challenging for astronomers to conduct research. Students may want to learn about DarkSky International, one of many organizations working to reduce light pollution in cities and towns around the world.
Environmental Principles & Concepts
Teacher Reflection Questions
Today’s lesson presented many opportunities for divergent reasoning strategies. Think about which students haven’t shared their strategies in class lately. Were there missed opportunities to highlight their thinking during recent lessons? How can you take advantage of those opportunities when they arise?