Area and perimeter unit

This unit will introduce and practice the concepts of area and perimeter. This unit uses resources of Shodor Education Foundation, Inc. Permission has been granted for the use of the materials as part of the workshop “Interactivate Your Bored Math Students.”

A lesson plan for grades 3–4 Mathematics

By Bonnie Boaz

Learn more

• The Shodor Education Foundation, Inc. Interactive math activities
• NCDigIns Help students become proficient in mathematics with this formative assessment diagnostic tool.

Related pages

• Inside, outside, and all around: Students will distinguish between perimeter, area, and volume. They will use tangrams and graph paper to create two-dimensional figures that will be measured for area and perimeter. By creating layers of centimeter cubes, the students will explore the concept of volume.
• Interior designers: Working with area: In this lesson for grade seven, students will act as interior designers, and will measure the walls of the classroom to determine the area of each wall.
• Woodworkers and finishers: Working with area: In this lesson, students participate in a furniture-finishing scenario in which they draw and calculate the area of a set of tabletops with different shapes.

Related topics

• Learn more about area, geometry, mathematics, and perimeter.

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Learning outcomes

Students will calculate the area and perimeter of a random shape on a grid.

Teacher planning

Time required for lesson

4 days

Materials/resources

pencil and paper

Technology resources

Either a computer lab or one classroom computer. Internet access and a color monitor are required.

Activities

Day 1

1. Ask students to recall information about polygons. You might ask students to consider how they might trace the perimeter of a polygon that is drawn on the board, or you may begin the day by running the perimeter of the school!
2. Let the students know what it is they will be doing and learning today. Say something like this:
   
   Today, Class, we will be talking more about the perimeter of polygons. We will learn exactly what this term means, and we will learn how to calculate the perimeter of random shapes.

   We are going to use the computers to learn about perimeter, but please do not turn your computers on or go to this page until I ask you to. I want to show you a little about the Perimeter Explorer applet first. Click on the Help tab for directions.

   (I always emphasize RIM in peRIMeter. I say that we are measuring the outside RIM of our shape.)
3. Do the Perimeter Explorer Activity.

Day 2

Explain the term “area” and give examples of how to calculate the area of random shapes using Area Explorer. Click on the Help tab for directions.

Day 3

Use Shape Explorer to practice both area and perimeter. Click on the Help tab for directions.

Day 4

Assess student understanding of area and perimeter skills by observing and recording students’ use of the applets from Days 1–3. See Assessment section.

Assessment

Given ten random shapes on a grid, the students will be able to calculate the area and perimeter.

Rubric for scoring:

• 9–10 correct: 5 points
• 7–8 correct: 3 points
• 6 correct: 1 point
• less than 6 correct: 0 points

You may wish to observe students calculate area and perimeter individually or in small groups, while other students practice. Students may also record their own results.

Supplemental information

Comments

Another option for independent practice is to have the students work in pairs (carefully chosen so that both students are of the same ability group). Have them race to find the correct area and perimeter using the Shape Explorer applet. Who ever wins gets a point. At the end of the allotted time for the game give the winning member of each pair a reward of some type.

This plan borrows heavily, with permission, from Shodor.org. You may want to explore their website for more classroom ideas.