Math Background

Lesson: Finding Perimeter and Area
Introducing the Concept

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Introduce students to the concept of perimeter and area with this hands-on activity.

Materials: worksheet (PDF file), 25 regular paper clips, and 25 one-and-one-fourth-inch square tiles for each student or pair of students

Preparation: Distribute the worksheets (PDF file), paper clips, and square tiles. If square tiles are not available, make one-and-one-fourth-inch squares from posterboard or construction paper.

Prerequisite Skills and Background: Students should know how to measure length using nonstandard units. They should also know the names and attributes of polygons.

  • Ask:How many sides does the polygon at the top of the page have? (4) What is the name of the polygon? (rectangle)
  • Say:Find the distance around the rectangle using paper clips as the unit of measure. Place the paper clips end to end along each side.
  • Ask:What is the distance around the rectangle? (12 paper-clip units)
    Encourage students to include “units” in the answer.
  • Say:The distance around a figure is its perimeter. The perimeter of the rectangle is 12 paper-clip units.
  • Ask:How many sides does the polygon below the rectangle have? (6) What is the name of this polygon? (hexagon)
  • Say:Find the perimeter of the hexagon.
  • Have students place paper clips end to end along each side of the hexagon.
  • Ask:What is the perimeter of the hexagon? (18 paper-clip units)
  • Say:Put the paper clips aside and cover the rectangle with square units. Don't overlap any squares.
  • Ask:How many square units did you use to cover the rectangle? (8 square units)
    Encourage students to include “square units” in the answer.
  • Say:The number of square units needed to cover a figure without overlapping is the area. The area of the rectangle is 8 square units.
  • Say:Find the area of the hexagon.
  • Have students cover the hexagon with square units.
  • Ask:What is the area of the hexagon? (16 square units)
  • Ask:What is the difference between perimeter and area?
    Students should realize that perimeter is the number of units, or distance, around a figure and area is the number of square units that cover a figure.
Houghton Mifflin Math Grade 3