# Find The Perimeter: Real Life Objects

• Math
• 90 minutes
• Standards: 3.MD.D.8
• no ratings yet
September 12, 2015

This lesson on perimeter will let your students walk around the class to see the border, use a measuring tape to measure the walls in their classroom, and enable them to understand how math is related to real life!

### Learning Objectives

Students will be able to find the perimeter of various shapes.

## Lesson

### Introduction (10 minutes)

• Ask your students if they know what the word perimeter means.
• Remind them that perimeter is the length of the border of a shape.
• Ask your students to make a line and walk around the classroom, touching the walls.
• Explain to your students that the walls are the border of the classroom.
• Tell them that if they wanted to find the perimeter of the classroom, they would measure the length of the walls and add them.

### Explicit Instruction/Teacher Modeling (10 minutes)

• Draw a rectangle on the board.
• Put the measurement of the sides of the rectangle next to the sides.
• Invite a student to come to the board and find the perimeter.
• Repeat the above bullets for a square and a triangle.

### Guided Practice/Interactive Modeling (20 minutes)

• Ask your students to complete the Geometry: Perimeter worksheet with a partner.
• Go over the worksheet with your students as a class.

### Independent Working Time (30 minutes)

• Instruct your students to complete the Presenting Perimeter worksheet.
• Go over the worksheet with your students as a class.

## Extend

### Differentiation

• Enrichment: Ask your students to create a drawing with polygons such as rectangles, squares, pentagons, hexagons, etc. Ask your students to use a ruler to measure the sides in centimeters. After that, ask your students to find the perimeter of their pictures. Instruct your students to find the perimeter of each shape in the picture separately first. After that, have them add the perimeter of each shape to find the perimeter of the entire picture.
• Support: Instruct your students to get a textbook. Ask your students to cover the border in blocks. Explain to your students that they have to add the sides of the book to find the perimeter. Ask them to find the perimeter of the book by counting the blocks on each side and adding them. After that, ask one student at a time to create a shape using blocks. Ask the other students to find the perimeter of that shape. Repeat this until your students are comfortable finding the perimeter.

## Review

### Review and Closing (10 minutes)

• Go around the class and assign each student a number from one to four.
• Assign each group to one wall of the classroom. For example, tell your students that everyone in group 1 should gather toward the front of the classroom.
• Hand each group a measuring tape and a sheet of paper.
• Ask each group to measure the length of the wall.
• Remind your students to work together to get the correct answer.
• Set the timer to 5 minutes.
• After your students are done getting the measurement, invite students to come to the board and write the measurement for their group.
• Ask students to find the perimeter on their own. Go over the perimeter to make sure that your students added correctly.