Shapes and Volume

Lesson 16

Math

Unit 3

5th Grade

Lesson 16 of 16

Objective


Classify triangles based on side and angle measures.

Common Core Standards


Core Standards

  • 5.G.B.3 — Understand that attributes belonging to a category of two-dimensional figures also belong to all subcategories of that category. For example, all rectangles have four right angles and squares are rectangles, so all squares have four right angles.
  • 5.G.B.4 — Classify two-dimensional figures in a hierarchy based on properties.

Foundational Standards

  • 4.G.A.2

Criteria for Success


  1. Classify triangles according to their side length as equilateral, isosceles, and scalene. 
  2. Classify triangles according to their angle measures as acute, right, and obtuse. 
  3. Understand that a regular polygon is a polygon whose sides are all the same length. 
  4. Draw conclusions about the classifications of triangles according to their properties (e.g., an equilateral triangle must be an acute triangle) (MP.7).

Tips for Teachers


Lesson Materials

  • Triangles Template (1 per student or small group) — This material should be cut into pieces before the lesson.
  • Right-angle tool (1 per student) — This can be any tool used to verify right angle measures, e.g., a protractor, the corner of a piece of paper, etc.
  • Ruler (1 per student) — This can be any tool used to verify equal lengths, e.g., the edge of a piece of paper, etc.
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Anchor Tasks

25-30 minutes


Problem 1

a.   Sort the shapes (cut out from Triangles Template) into as many categories as you’d like. Then explain how you sorted them.

b.   Sort the shapes (cut out from Triangles Template) in another way. Then explain how you sorted them.

Guiding Questions

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Student Response

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Problem 2

a.   What are the characteristics shared by shapes within circle A? Within circle B? Within circle C? Double-check to make sure that any shapes that have that characteristic are contained within the circle and any shapes that don't lie outside of the circle.

b.   Where would you place a rectangle that does not have four sides of the same length? Why?

c.   What kind of shape could go in the center of this Venn Diagram? Be specific about its properties. If there could not be a shape that belongs in the center, justify your reasoning.

Guiding Questions

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Student Response

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References

Illustrative Mathematics What do these shapes have in Common?

What do these shapes have in Common?, accessed on Aug. 9, 2017, 4:31 p.m., is licensed by Illustrative Mathematics under either the CC BY 4.0 or CC BY-NC-SA 4.0. For further information, contact Illustrative Mathematics.

Modified by Fishtank Learning, Inc.

Problem Set

15-20 minutes


Discussion of Problem Set

  • Look at #2. Why is (a) always true but (b) is only sometimes true?
  • Look at #3. For which cells were you unable to draw a triangle? Why?
  • Look at #4. What is the term for a regular polygon that is a triangle?

Target Task

5-10 minutes


Problem 1

Which of the following best describes the triangle below?

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Student Response

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Problem 2

Which of the following statements is true about every scalene obtuse triangle?

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Student Response

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Additional Practice


The Extra Practice Problems can be used as additional practice for homework, during an intervention block, etc. Daily Word Problems and Fluency Activities are aligned to the content of the unit but not necessarily to the lesson objective, therefore feel free to use them anytime during your school day.

Word Problems and Fluency Activities

Word Problems and Fluency Activities

Help students strengthen their application and fluency skills with daily word problem practice and content-aligned fluency activities.

Lesson Map

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Topic A: Volume of Three-Dimensional Figures

Topic B: Classification of Two-Dimensional Shapes

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