The Greedy Triangle by Marilyn Burns

Mathematical Strand:

Geometry

Topic:

Students will review angles, sides, and properties of basic shapes.

Grade Level:

4-6

Lesson Created by:

Tracy Tauschek, Woodrow Wilson Elementary, Manhattan, KS

Lesson Description:

Materials

• Geoboards, rubber bands, The Greedy Triangle
  

1. Launching the Lesson

1. Give the students each a geoboard and ask them to make as many different triangles as they can. Let them tell about the triangles they made. Discuss different kinds and shapes of triangles.
   
2. Have the students clear the geoboards except for one basic triangle in the center. Model on the overhead.
   

2. Developing the Lesson

1. Read The Greedy Triangle. As you read have the student change the number of angles and sides that their shape has to fit the story. Model on the overhead.
   
2. Go back through the book and list the shapes, number of sides, number of angles, and other properties.
   
3. This is a great introduction or review of shapes.
   
4. Ask the students if they think there are any other reasons besides math to read this book. Help the students understand that the triangle kept changing but it did not really make him happy. How does this relate to their own lives?
   

3. Closure/Discussion/Elaboration

1. Have the students make their own books using a different shape.
   
2. Have students make a poster or card telling the triangle why he is great just he way he is! Or have student make posters or cards telling people in the class why they are great!