Classifying 2-D shapes

● 5.G.3 Understand that attributes belonging to a category of two-dimensional figures also belong to all subcategories of that category.

● 5.G.4 Classify two-dimensional figures in a hierarchy based on their attributes.

Vocabulary:

• attribute
• subcategory
• hierarchy

Students can use graphic organizers such as flow charts or T-charts to compare and contrast the attributes of geometric figures. Have students create a T-chart with a shape on each side. Have them list attributes of the shapes, such as number of sides, number of angles, types of lines, etc. they need to determine what’s alike or different about the two shapes to get a larger classification for the shapes and be able to explain these properties.

Examples:

(1) Examine whether all quadrilaterals have right angles. Give examples and non-examples.

(2) If the opposite sides on a parallelogram are parallel and congruent, then rectangles are parallelograms. A sample of questions that might be posed to students include:

(a)A parallelogram has 4 sides with both sets of opposite sides parallel. What types of quadrilaterals are parallelograms? Explain.

(b) Regular polygons have all of their sides and angles congruent. Name or draw some regular polygons. Explain your drawings.

(c) All rectangles have 4 right angles. Squares have 4 right angles so they are also rectangles. True or False? Explain your reasoning.

(d) A trapezoid has 2 sides parallel so it must be a parallelogram. True or False? Explain your reasoning.

(3) Pose questions such as, “Why is a square always a rectangle?” and “Why is a rectangle not always a square?” Expect students to use precision in justifying and explaining their reasoning.

(4) Explore why: A right triangle can be both scalene and isosceles, but not equilateral. A scalene triangle can be right, acute and obtuse.

(5) Create a Hierarchy Diagram using the following terms: Students should be able to reason about the attributes of shapes by examining: ● What are ways to classify triangles? ● Why can’t trapezoids and kites be classified as parallelograms? ● Which quadrilaterals have opposite angles congruent and why is this true of certain quadrilaterals? ● How many lines of symmetry does a regular polygon have?

I Can Statements

• I can classify two-dimensional figures by their attributes.
• I can explain two-dimensional attributes can belong to several two-dimensional figures.
• I can identify subcategories using two-dimensional attributes.

Howard County Schools Resources for 5.G.3 - https://hcpss.instructure.com/courses/108/pages/5-dot-g-3-about-the-math-learning-targets-and-rigor

 This page includes teacher notes, lesson plans, print resources

LearnZillion video links, and web resources Howard County Schools Resources for 5.G.4 - https://hcpss.instructure.com/courses/108/pages/5-dot-g-4-about-the-math-learning-targets-and-rigor

 This page includes teacher notes, lesson plans, print resources

LearnZillion video links, and web resources Always, Sometimes, Never (5.G.3)- https://www.illustrativemathematics.org/content-standards/5/G/B/3/tasks/1941

● The purpose of this task is to have students reason about different kinds of shapes based on their defining attributes and to understand the relationship between different categories of shapes that share some defining attributes.

What is a Trapezoid? (5.G.4) https://www.illustrativemathematics.org/content-standards/tasks/1505

● The purpose of this task is for students to compare different definitions for trapezoids.

Learn Zillion Videos https://learnzillion.com/resources/72818-understand-attributes-of-two-dimensional-figures-and-classifying-figures-in-a-hierarchy-5-g-b-3-5-g-b-4

● Videos that support 5.G.3 and 5.G.4

Resources Engage NY Grade 5, Module 5 - Addition and Multiplication with Volume and Area - https://www.engageny.org/resource/grade-5-mathematics-module-5

 Topic D covers 5.G.3 and 5.G.4 Examples of activities - see 5.G.3 and 5.G.4 www.k-5mathteachingresources.com