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Types of Triangles




4, 5  


1. MA Standard: 5.G.1: Students will identify, describe, and compare triangles: isosceles, right, equilateral, scalene, obtuse, and acute.

2. Students will discover a rule that states whether or not it is possible to construct triangles from given lengths.

Brainpop Movie
on triangles 
Promethean Flipchart :Classifying Triangles 
Illuminations: Resources for Teaching Math Lesson on “What’s so important about Triangles?”  
Grid paper


1. State Objectives for the day.

2. Show Brainpop movie

3. Start Flipchart on Triangles. Have students take out thier Geometry Study Guides. Students will add the new definition, illustration and drawing of the different types of triangles as we watch the Flipchart.


M.Ed. in Curriculum & Instruction: Math



4.  During the flipchart, there are pages for guided practice.  Students will also use the interactive board as they fill in the guided practice pages.

5.  Pose Question to the class: Can any three lengths be the sides of a triangle? Have students write answers on sticky notes.

6. Explain task. Students will create different triangles with specified measurements using grid paper and tape. They will label the triangles with the letters  Students will also identify the type of triangle they make. They will discover which triangles can be made and classify them. They will discover the rule that the 2 smaller sides must be greater than the largest side.

7.  Close with descriptions of triangle characteristics.

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