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K–12 teaching and learning · from the UNC School of Education

Investigating the concept of triangle and properties of polygons

http://standards.nctm.org/document/eexamples/chap4/4.2/

A lesson plan for Grades K–2 Mathematics

Provider: National Council of Teachers of Mathematics

About this resource

Appropriate grades
K–2
Subjects
mathematics (geometry)
Provider
National Council of Teachers of Mathematics

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This two-part example from Illuminations describes activities using interactive geoboards to help students identify simple geometric shapes, describe their properties, and develop spatial sense. This first part, Making Triangles, focuses attention on the concept of triangle, helping students understand the mathematical meaning of a triangle and the idea of congruence, or sameness, in geometry. In the next part, Creating Polygons, students make and compare a variety of polygons, describing the salient properties of the shapes they create.

E-Math Investigations are selected e-examples from the electronic version of the Principles and Standards of School Mathematics (PSSM). The e-examples are part of the electronic version of the PSSM document. Given their interactive nature and focused discussion tied to the PSSM document, the e-examples are natural companions to the i-Math investigations.

North Carolina Curriculum Alignment

Mathematics (2004)

Grade 1

  • Goal 3: Geometry - The learner will identify, describe, draw, and build basic geometric figures.
    • Objective 3.01: Identify, build, draw and name parallelograms, squares, trapezoids, and hexagons.
    • Objective 3.03: Compare and contrast geometric figures.
    • Objective 3.04: Solve problems involving spatial visualization.

Grade 2

  • Goal 3: Geometry - The learner will perform simple transformations.
    • Objective 3.01: Combine simple figures to create a given shape.
    • Objective 3.02: Describe the change in attributes as two- and three-dimensional figures are cut and rearranged.
    • Objective 3.03: Identify and make:
      • Symmetric figures.
      • Congruent figures.

Kindergarten

  • Goal 3: Geometry - The learner will explore the concepts of geometry.
    • Objective 3.01: Identify, build, draw, and name triangles, rectangles, and circles; identify, build, and name spheres and cubes.
    • Objective 3.02: Compare geometric shapes (identify likenesses and differences).
    • Objective 3.03: Model and use directional and positional vocabulary.
    • Objective 3.04: Complete simple spatial visualization tasks and puzzles.