Classifying Triangles —Lesson Module

Primary Content Knowledge/Ideas

Focal Practices

• Triangles can be classified by relationships between line lengths, or line properties: Scalene, Isosceles, and Equilateral

• Triangles can be classified by relationships between angle measurements, or angle properties: Acute, Right, and Obtuse • Triangles can be identified and classified by relationships between line and angle properties in a triangle:

• 1. a right isosceles triangle
  2. a right scalene triangle
  3. an acute scalene triangle
  4. an acute isosceles triangle
  5. an acute equilateral triangle
  6. an obtuse scalene triangle
  7. an obtuse isosceles triangle

• Students will identify and reason with relationships between lines and angle properties in triangles to develop a system of classifying triangles.

• Students will use a variety of tools to visualize, construct, and explain the development of geometric relationships in triangles; ranging from rulers to protractors to Zometool models.