Lesson 8
Sort Triangles
Lesson Purpose
Lesson Narrative
The purpose of this lesson is to sort triangles into categories, recognizing right triangles as a category. Students also examine side lengths and notice that sometimes all 3 side lengths are different, sometimes 2 side lengths are equal, and sometimes all 3 side lengths are equal. Students identify right triangles and examine the possible angles that a triangle can have. For example, there are triangles with 3 acute angles but a triangle can only have one right or obtuse angle. Students should have access to straight edges, protractors, and patty paper throughout this lesson.
- Engagement
- MLR7
Learning Goals
Teacher Facing
- Classify triangles based on angle measurements and side lengths.
Student Facing
- Let’s sort triangles.
Required Materials
Materials to Copy
- Card Sort Triangles (Grade 5)
Required Preparation
Activity 1:
- Create a set of cards from the blackline master for each group of 2.
Activity 2:
- Gather materials from previous activity:
- Triangle Cards
Lesson Timeline
Warm-up | 10 min |
Activity 1 | 20 min |
Activity 2 | 15 min |
Lesson Synthesis | 10 min |
Cool-down | 5 min |
Teacher Reflection Questions
Suggested Centers
- Which One? (K–5), Stage 7: Grade 5 Shapes (Addressing)
- How Are They the Same? (1–5), Stage 5: Grade 5 Shapes (Addressing)
- How Are They the Same? (1–5), Stage 4: Grade 4 Shapes (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 |