
Geometry


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The Greedy Triangle Author: Marilyn Burns Illustrator: Gordon Silveria Publisher: Scholastic Inc. Copyright: 1994 ISBN: 0590489917 Number of Pages: 36 Ohio Standards Alignment: Grades preK–2
This story invites children to imagine what happens to shapes as they get more sides and more angles. As the shapeshifter keeps adding more sides to a triangle, the text introduces children to the names of the resulting polygons and shows representations of them in the real world. The author includes a discussion of the mathematical ideas and suggestions for extensions at the end of the book.
Go to: How to Use This Book Highlights and Insights Related ORC Resources Ohio Standards


How to Use This Book

 Children take a walk to look for shapes in the real world. Focus on a single shape, such as a triangle, and have them draw what they see.
 Have students tell you what they have seen in the shape of a triangle after you read the first four pages. After reading the next four pages, ask the students to identify quadrilaterals that they see. Continue to use the book in this way until finished.
 Children select a polygon and think about what it might be a part of. When they have an idea, they should attach their polygon to a piece of paper and draw a picture around it.
 Create a picture using the various shapes from the book. Have the children cut out an assortment of these shapes and make a "cool" picture with their shapes.


Highlights and Insights

 The book is meant engage children in the topic of polygons. Each new polygon stimulates the child's imagination as to where that polygon could be found in the real world.
 Accurate information is included about the subject of polygons, and the author explains that polygons can approach being a circle as the number of sides increases, but that a circle is not itself a polygon.


Related ORC Resources

Going on a Shape Hunt: Integrating Math and Literacy Resource Type: Lessons Discipline: Mathematics, Reading Grades: Grades K–2 Professional Commentary: In this lesson, students are introduced to geometric shapes through a readaloud session with a picture book. Using models to learn the names of shapes, students work together and individually to locate shapes in their realworld environment.... Mathematics and Children's Literature 1: Shapes and Poetry Resource Type: Lessons Discipline: Mathematics Grades: Grades 2–4 Professional Commentary: This lesson is the first of three multitopic lessons that focus on activities motivated by mathematically related stories from children's literature. The teacher reads the poem "Shapes" from A Light in the Attic, and students use cutouts or draw shapes to depict the story in the poem.... Investigating Shapes: Triangles Resource Type: Lessons Discipline: Mathematics Grades: Grades PreK–2 Professional Commentary: In this fourlesson unit, students identify characteristics of triangles, manipulate real and electronic geoboards to construct triangles, and describe the triangles' relative locations. In addition, through music and observation, students identify triangles in their environment.... ODE Assessment Item, Grade 3: Sort Shapes by Characteristics Resource Type: Assessments Discipline: Mathematics Grades: Grades K–3 Professional Commentary: Students must select a shape with the same characteristics as another group of shapes. This multiplechoice question is a sample item used in the 2005 Ohio Grade 3 Achievement Test (see Overview of Ohio's Assessment System)....


Ohio Standards

Geometry and Spatial Sense StandardBenchmarks (K2) A. Describe and create plane figures: circle, rectangle, square, triangle, hexagon, trapezoid, parallelogram and rhombus, and identify them in the environment. Grade Level Indicators (K) 1. Identify and sort twodimensional shapes and threedimensional objects. For example:
a. Identify and describe twodimensional figures and threedimensional objects from the environment using the child's own vocabulary.
b. Sort shapes and objects into groups based on studentdefined categories.
c. Select all shapes or objects of one type from a group.
d. Build twodimensional figures using paper shapes or tangrams; build simple threedimensional objects using blocks. Grade Level Indicators (1) 1. Identify, compare, and sort twodimensional shapes; i.e., square, circle, ellipse, triangle, rectangle, rhombus, trapezoid, parallelogram, pentagon, and hexagon. For example:
a. Recognize and identify triangles and rhombuses independent of position, shape or size; and
b. Describe twodimensional shapes using attributes such as number of sides and number of vertices (corners, or angles). Grade Level Indicators (preK) 3. Identify, name, create and describe common twodimensional shapes in the environment and play situations (e.g., circles, triangles, rectangles, and squares). 

