The Best Book for Teaching 2D Shapes: The Greedy Triangle Lesson Plan
This exciting lesson plan will have your students buzzing with excitement about 2D shapes and geometry! We’re diving into the wonderful world of polygons using the captivating book, “The Greedy Triangle” by Madilyn Burns. So, fasten your seatbelts, and let’s embark on this thrilling geometric adventure together!
Why you should teach 2D shapes with this Greedy Triangle lesson
In this lesson plan, we want students to confidently identify, describe, and create 2D shapes/polygons with up to 12 sides. This includes triangles, quadrilaterals, pentagons, hexagons, heptagons, octagons, decagons, and beyond! The lesson follows the 5E instructional model, with 5 phases to Engage, Explore, Explain, Elaborate, and Evaluate.
We aim to deepen students’ understanding of geometry by exploring the attributes and properties of shapes through hands-on activities. You can find everything you need for this lesson by clicking the button below!
Reading "The Greedy Triangle" by Madilyn Burns
Now, it’s time to meet our adventurous friend, “The Greedy Triangle”!
“The Greedy Triangle” Summary from Scholastic.com: A triangle visits a local shapeshifter to add another angle to his shape. But, he becomes greedy and continues adding angles until he’s completely transformed. Kids will love this fun & colorful introduction to 2D shapes!
As you read this book aloud, be sure to ask thought-provoking questions to encourage active participation. A few examples of questions include “What shapes do you see on this page?” or “Why do you think the triangle wants to become different shapes?”
During the entire read-aloud, students will participate in a popsicle stick activity to explore 2D polygons. As the Greedy Triangle adds sides, vertices, and angles, so will the students using the popsicle sticks. For the full instructions on this engaging activity, click here!
Exploring 2D Shapes with "The Greedy Triangle" Lesson Plan
After enjoying the story, let’s explore polygons with up to 12 vertices in three fun, interactive math centers! Students will rotate through each station to create shapes with exciting, hands-on experiences.
The lesson includes 2D Polygon Cutouts that can be used in all 3 centers as a helpful visual aid. They are available in both color and black/white, so you can choose what works best for you and your students!
These stations will help students reinforce their understanding and apply their knowledge of 2D shapes. The full lesson plan on TPT has all the specific details about each math station and how to successfully implement them in your classroom. Check it out by clicking the button below!
Discussing Vocabulary & Attributes of 2D Shapes
Next, students will discuss vocabulary and attributes during a 2D Polygons PowerPoint Presentation, featuring 33 total slides with adorable clipart (also available as a convenient PDF).
During the presentation, you’ll elaborate on the vocabulary words encountered previously in the math center activities. By referring back to those stations, you’ll reinforce the students’ understanding of 2D shapes in a meaningful way.
This PowerPoint explains the attributes of polygons, ranging from simple triangles to more complex shapes with up to 12 sides. Students will also be guided to notice the pattern between the number of sides and vertices each shape possesses.
This resource is sure to foster a deeper understanding of 2D shapes!
Evaluating Student Understanding throughout this 2D Shapes Lesson
Ensuring your students grasp the concept of 2D shapes is crucial, and there are a variety of assessment strategies in place throughout this lesson plan to make it happen!
You should also be checking for comprehension throughout the lesson by asking questions and observing. By incorporating the included Bloom’s taxonomy questions, you can challenge their thinking and encourage deeper understanding. These informal assessments through class discussions will provide valuable insights into students’ progress.
At the end of the lesson, your students will create a Polygon Glossary worksheet to describe all of the shapes discussed today. This worksheet will be used to assess their understanding of 2D shapes with an included answer key, and there’s also a provided rubric to ensure they’re mastered all the shape vocabulary.
Extending Learning to Excite Students about 2D Shapes
I like to think of Extension activities as an additional “E” in the 5E instructional model. Here are a few ideas for ways to extend learning even further:
- Polygon “I Spy” – Encourage students to find 2D shapes around the classroom.
- Shape Show & Tell – Allow students to bring in objects that represent different 2D shapes.
- Shape Scavenger Hunt – Students can work in pairs to hunt for shapes around the school, and they can keep a log of what they find in their math journals.
- Online Shape Games – Your students can explore websites that reinforce shape recognition and attributes. I love this list of 2D Shapes Games from TopMarks.com!
- Additional Books About Shapes – Click here to view a list of additional books about 2D polygons!
The Greedy Triangle: An Exciting Resource for Teaching 2D Shapes
I hope this Greedy Triangle 2D Shapes Lesson Plan ignites a spark of curiosity and enthusiasm in your classroom. Remember, teaching shapes can be an adventure filled with creativity and endless possibilities. I encourage you to give these activities a try and then share your experiences in the comments below — I can’t wait to hear from you!
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