Abstract
Students will learn about perimeter and the units used to measure perimeter using a variety of materials including their hands, feet, rulers, and computer applets.
Objectives
Upon completion of this lesson, students will:
- have practiced finding perimeter of rectangular shapes and irregular shapes with right angles.
- understand which units of measure are appropriate for measuring perimeter.
Standards Addressed
Grade 3
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Geometry
- The student solves problems using perimeter or area.
Grade 4
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Geometry
- The student solves problems using perimeter or area.
Grade 5
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Geometry
- The student solves problems (including real-world situations) using perimeter or area.
Third Grade
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Geometry
- Reason with shapes and their attributes.
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Measurement and Data
- Geometric measurement: recognize perimeter as an attribute of plane figures and distinguish between linear and area measures.
3rd Grade
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Measurement
- The student will demonstrate through the mathematical processes an understanding of length, time, weight, and liquid volume measurements; the relationships between systems of measure; accurate, efficient, and generalizable methods of determining the perim
- The student will demonstrate through the mathematical processes an understanding of length, time, weight, and liquid volume measurements; the relationships between systems of measure; accurate, efficient, and generalizable methods of determining the perimeters of polygons; and the values and combinations of coins required to make change.
4th Grade
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Measurement
- Standard 4-5: The student will demonstrate through the mathematical processes an understanding of elapsed time; conversions within the U.S. Customary System; and accurate, efficient, and generalizable methods of determining area.
Student Prerequisites
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Technological:
Students must be able to:
- perform basic mouse manipulations such as point, click and drag
- use a browser for experimenting with the activities
Teacher Preparation
- access to a browser
- construction paper and pencil
- rulers and graph paper
Key Terms
Lesson Outline
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Focus and Review
Begin the lesson by asking the students if anyone has a fenced yard and ask them to think about how you might figure out how much fencing was required.
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Objectives
Let student know what they will be doing and learning today. Say something like this:
- Today we are going to be learning about the concept of perimeter and how to calculate perimeter.
- 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.
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Teacher Input
- Have the class measure the perimeter of their desk top using their hands as the unit of measure.
- Discuss the different answers the students calculated.
- Discuss why the answers differed.
- Introduce the term perimeter.
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Guided Practice
- Have the students work in pairs and measure the perimeter of 4 or 5 different objects around the room using different units: hands, feet, pencils, in, ft, etc.
- Monitor the students' progress.
- Have a couple of students share their examples.
- Discuss why it might be necessary to have a standard unit like: inches, feet, or meters.
- Discuss why someone might need to know the perimeter of something. (Example: fencing a yard)
- Demonstrate how to use the Perimeter Explorer. (You may want to specify certain area settings.) Have the students answer a couple of computer generated problems with you.
- Demonstrate how to draw the figure generated by the computer on a piece of graph paper.
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Independent Practice
- Have the students work either alone or in groups of two with the Perimeter Explorer.
- So you can check their progress, have the students copy the computer generated figures on a piece of graph paper.
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Closure
- Draw a grid on the board and draw a few shapes in the grid.
- Call on several different students to help you determine the perimeter of each shape.
- Review the meaning of the word perimeter.
- Review the different units used to measure perimeter.