# 2-D Shapes

• Math
• 40 minutes
• Standards: 2.G.1
• no ratings yet
October 5, 2015

Shape up your students' understanding of geometrical attributes with this hands-on math lesson. Students will gain a better understanding of how to describe a shape by the number of edges and vertices it has, rather than by its name.

### Learning Objectives

Students will be able to name shapes according to the number of edges and vertices.

## Lesson

### Introduction (3 minutes)

• Display a triangle to the class, either by drawing it on the whiteboard or using an interactive whiteboard. Ask your students to call out the name of the shape.
• Discuss the shape attributes as a class. Great discussion questions include: How many sides does a triangle have? Are they straight or curved? How many corners does a triangle have?
• Point to each corner on the triangle. Explain to the class that a vertex is the place where two sides meet in a corner. Tell the class that a triangle has three vertices, the plural word for vertex.
• Count the sides of the triangle together. Explain that each side is a line that connects two vertices, also known as an edge.
• Announce to the class that today they will learn how to describe the attributes of a shape to describe it, instead of always just using its name.

### Explicit Instruction/Teacher Modeling (7 minutes)

• Draw and label a rectangle and pentagon on the board.
• Explain that shapes are made up of a set of sides or curved segments. Straight sides are the edges of each shape.
• Draw a circle on the whiteboard. Ask the class how many edges a circle has.
• After some discussion, tell the class that a circle doesn't have any edges or vertices, since there aren't any straight lines or corners on a circle.
• Point to the rectangle and demonstrate how to count the edges and vertices. Explain to students how the number of edges and the number of vertices are the same.
• Point to the pentagon and count the number of edges and vertices.

### Guided Practice/Interactive Modeling (10 minutes)

• Give each student the following pattern blocks: triangle, trapezoid, hexagon, and square.
• Ask students to hold up the correct pattern block as you call out the number of edges or vertices a shape has. As you call out numbers, remind students that the number of edges and vertices a shape has is the same.

### Independent Working Time (10 minutes)

• Pass out a copy of the 2-Dimensional Shapes worksheet to each student.
• Have students complete the sheet on their own.

## Extend

### Differentiation

• Enrichment: Challenge advanced students to draw and label more advanced shapes, such as hexagons, heptagons, octagons, and decagons. Instruct them write a riddle for each shape name on a sheet of paper, which includes the correct number of edges and vertices the shape has.
• Support: Encourage struggling students to use pattern blocks to trace the triangle, hexagon, and trapezoid. Ask them to count the number of sides and to write the number beside the drawing.

## Review

### Assessment (5 minutes)

• Pass out a sheet of drawing paper to each student. Instruct your students to draw and label a pentagon on the paper.
• Remind students that they should count and label the edges and vertices on the paper as well.

### Review and Closing (5 minutes)

• Ask students to look around the classroom and name objects with three, four, or five edges.
• Make a list of all the objects.