The Greedy Triangle

Students review geometric terms by making predictions about what the Greedy Triangle will become as the teacher reads the book, The Greedy Triangle. Students will create geometric creatures after the review.

A lesson plan for grade 3 Mathematics

By Renee Allen

Learn more

Related pages

• In math, "elegant" means "cool"!: An elegant solution to a math problem is one that requires less time and work. Encouraging students to find such solutions will help them build number sense or numeracy.
• Math Fun: We have compiled some of our favorite mathematics instructional resources to help students develop a sense of numbers and how they are used by us everyday. Students will have fun practicing their skills and trying new problem-solving ideas.
• Beginning lesson on Coordinate Grids-First Quadrant: Students will investigate the first quadrant of the Cartesian coordinate system. They will use online activities developed by Shodor.org to identify the coordinates of points, or plot specific points. Then students will progress to an activity where they direct a robot through a mine field laid out on the coordinate plane. Permission has been granted for the use of the materials as part of the workshop - "Interactivate Your Bored Math Students" by Shodor Education Foundation, Inc.

Related topics

• Learn more about mathematics.

Help

Please read our disclaimer for lesson plans.

Legal

Learning outcomes

Students will:

• review geometric terms by making predictions about how the triangle changes in the book.
• create an animal using the concepts of the geometric terms that were previously reviewed.
• analyze the theme of the book.

Teacher planning

Time required for lesson

45.00 Minutes

Materials/resources

• colored pencils
• rulers
• yarn: 1 meter
• drawing paper
• sample shapes
• The Greedy Triangle by Marilyn Burns, Scholastic; (March 1, 1995) ISBN: 0590489917

Technology resources

None

Pre-activities

Working knowledge of geometric shapes.

Activities

1. Ask the riddle: What did the acorn say when he was all grown up? Answer: Geometry / “Gee, I’m a tree.”
2. State the objective of the lesson.
3. Teacher should tell the students that they are to make predictions about what the triangle becomes as the teacher reads the book. Also, tell the students to think about the theme of the book and be able to explain it.
4. Read the book. Discuss the book’s plot and theme.
5. Review the vocabulary in the attachment.
6. Teacher Discussion: Back in the days before cameras were invented, the only way you could show someone how something looked was to draw a picture of it. Today, we are going to pretend we are living in those times. Imagine you have just received a letter from an explorer who has discovered a strange animal. The explorer has not sent a drawing just a letter. It is going to be your job to draw a picture of the animal described in the letter. Remember, we are just pretending, so the animal can be really fantastic. Students can name their animals after they create them.
7. The teacher reads the following sentences one at a time. The students will draw what the teacher describes.
   
   • The animal has a body shaped like an equilateral triangle.
   • The head is shaped like a bumpy circle.
   • This creature has legs that are approximately one and one-half inches in length.
   • On each leg is a foot with three toes, and on each toe is a claw that is about one- quarter of an inch in length.
   • In the center of its body, it has a large spot shaped like a hexagon.
   • The facial features include a pair of pentagon shaped eyes, an octagon shaped nose and a mouth that is best described as a semicircle.
   • Upon its head are two parallel horns that appear to be sharp.
   • Its tail is furry and one meter in length.

Assessment

Check the accuracy of the shapes (i.e. pentagon-5 sides, octagon-8 sides,etc.). Have the students write a paragraph supporting the book’s theme with examples from the text.

Supplemental information

None

Related websites

http://www.mathgoodies.com/puzzles/polygon_cw.shtm

Comments

This geometric review integrates language arts and math. Most students are better at retaining information when it is atttached to something known or relevant. M. Burns presents the shapes in her book using ordinary and familiar things. Also, the shapes are reinforced as the students create their own geometric creatures.

This lesson can become the source for many fourth grade writing objectives, too. The creature could be described in a character analysis, become the main character in an imaginary narrative, be a first person narrator describing a day in his / her life, etc.

The website listed can be used as a review of geometric shapes or as an assessment tool.