Measuring Perimeter

Lesson Overview

Grade Level: Year 3
Date & Time: Tuesday, March 25th, 2025 – 1:35 p.m. – 2:15 p.m.
Subject: Mathematics
Topic: Measuring Perimeter in Metres
Duration: 40 minutes
Class Size: 15 Students
Ontario Mathematics Curriculum Area:

• Strand: Measurement
• Overall Expectation: E2. Measurement
• Specific Expectation: E2.1 – Use appropriate units of length to estimate, measure, and compare the perimeters of polygons and curved shapes and construct polygons with a given perimeter.

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Learning Objectives

By the end of the lesson, students will be able to:

✔ Define perimeter and explain why it is measured in metres.
✔ Measure real-world objects using metre sticks or measuring tapes.
✔ Calculate and compare different perimeters by adding side lengths.
✔ Work collaboratively to share strategies and findings.
✔ Reflect on the usefulness of perimeter in real-life situations.

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Success Criteria

Students will demonstrate their understanding by:

• Explaining the concept of perimeter in their own words.
• Correctly using measuring tools to determine the perimeter of objects.
• Accurately calculating and recording the perimeter of shapes.
• Collaborating with peers to discuss findings and problem-solve.

Assessment will be conducted through:

✅ Oral questioning to check for understanding.
✅ Observations during hands-on activities.
✅ Completion of a perimeter worksheet.
✅ Exit ticket reflection.

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Resources and Materials

🟢 Classroom Materials:

• Metre sticks or measuring tapes
• Whiteboard and markers
• Printout of worksheet (Pages 349-350)
• Chart paper for group results
• Sticky notes for exit ticket

🟢 Learning Environment:

• Students will sit at their desks facing the classroom TV for lesson instructions.
• Hands-on activities will take place within small groups.

🟢 Accommodations & Modifications:

• Pair lower-level learners with advanced peers for collaboration.
• Provide extra support from the teacher or teaching assistant when needed.
• Offer hands-on measurement alternatives for students who struggle with calculations.

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Lesson Structure

1️⃣ Introduction & Activation (10 min)

➡ Engage Students with a Hook – Ask:
"What do we use fences for?" (Encourage responses.)
Show a simple drawing of a garden or house and ask:
"If I want to put a fence around this, how much do I need?"

➡ Introduce the Concept of Perimeter

• Define perimeter as the total distance around a shape.
• Show Amira's Garden problem (p. 348) and discuss how to find its perimeter.

➡ Mini Lesson:

• Write an example shape on the board (e.g., a rectangle with sides 4m & 6m).
• Model how to add the sides: 4m + 6m + 4m + 6m = 20m.
• Ask: “Where else do we measure perimeter in real life?” (E.g., fences, tracks, buildings.)

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2️⃣ Guided & Independent Practice (20 min)

🔹 Guided Practice (10 min)

• Divide students into groups of 3.
• Give each group a measuring tool (metre stick/tape).
• Assign classroom objects to measure (whiteboard, desk, rug, or door frame).
• Groups record perimeter measurements & share them.

🔹 Independent Practice (10 min)

• Students complete worksheet exercises (p. 349-350)
• Encourage them to show their work by drawing & labelling shapes.
• Teacher circulates to assist those who need help.

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3️⃣ Consolidation & Reflection (10 min)

💬 Group Share-Out:

• Groups present their perimeter findings.
• Discuss similarities/differences in results.

🤔 Class Discussion – Real-Life Connections

• “When would you use metres instead of centimetres?”
  (Encourage students to think about when measuring large areas).

📝 Exit Ticket:
Each student writes one thing they learned about perimeter on a sticky note and places it on a class chart.

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Teacher Reflection (Post-Lesson)

✏ What worked well? (Engagement, participation, hands-on activity success?)
✏ What challenges did students face? (Measurement accuracy, number sense, collaboration?)
✏ How can I better support struggling students? (More practice, visual aids, interactive examples?)

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Teacher’s Notes

✅ This lesson aligns with the Ontario Mathematics Curriculum (2020), ensuring students grasp the fundamentals of perimeter through interactive learning.
✅ Next lesson will include introduction to perimeter in centimetres and how to apply perimeter knowledge to problem-solving tasks.
✅ Keep anecdotal observations for students who need additional support, as this will help in future scaffolding.

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Wow Factor for Teachers! ✨

💡 Interactive Learning: Instead of simply writing equations, students physically measure objects in the classroom, ensuring an engaging, hands-on approach.

💡 Real-World Application: Instead of just numbers, the lesson connects to real-life (e.g., fencing, playgrounds, tracks).

💡 Collaborative Problem-Solving: Students work in small teams, fostering teamwork while making learning social & enjoyable!

💡 Exit Ticket Reflection: Helps students solidify their understanding while informing the teacher of individual learning progress.

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Next Steps

🔜 Future Lessons:
📌 Lesson 6 – Perimeter in Centimetres (Comparing metres vs. centimetres!)
📌 Lesson 7 – Irregular Perimeters (How do we measure curved edges?)

📚 Recommended Resource for Teachers: Hands-On Math: Exploring Measurement through Inquiry-Based Learning

🚀 Let’s Make Learning Fun, Engaging, and Real-World Focused!