Lesson Plan Template
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Grade
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Subject
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Section
Third
Math
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Competency
Perimeter
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Aligned Standards
Measurement and Data
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Strand
3.MD.D.8
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Vocabulary
- Perimeter: The distance around the outside of a shape.
- Rectilinear shape: A shape with straight sides and right angles.
Find Perimeter of Irregular Shapes
Prerequisite Skill
Materials and Preparation
- Rulers for measuring lengths
- Grid paper for drawing rectilinear shapes
- TeachTastic Worksheet Pack for Perimeter of Rectilinear Shapes
- Markers or colored pencils for highlighting sides
- Whiteboard and markers for demonstrations
Learning Objectives
- Students will understand the concept of perimeter as the distance around a shape.
- Students will be able to calculate the perimeter of rectilinear shapes by summing the lengths of their sides.
- Students will apply their knowledge to solve word problems involving perimeter.
Introduction
Begin the lesson by showing students a simple rectilinear shape, such as an L-shaped polygon, on the board. Ask students if they know what the perimeter of the shape is. Explain that the perimeter is the distance around the shape and that today, they will learn how to calculate it by adding the lengths of all the sides.
Explicit Instruction/Teacher modeling
Demonstrate how to calculate the perimeter of the rectilinear shape displayed on the board. Start by identifying each side and labeling its length. Write down the lengths on the board and model how to add them together to find the total perimeter. Emphasize that all sides must be included in the sum.
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Guided Practice
Distribute the TeachTastic Worksheet Pack for Perimeter of Rectilinear Shapes. Guide the students through the first few problems, working together as a class. Use a ruler to measure sides if necessary, and ensure students understand how to sum the side lengths to find the perimeter. Allow students to highlight each side on the worksheet to keep track of their work.
Independent Practice
Students will complete the remaining problems in the TeachTastic Worksheet Pack independently. These problems will vary in difficulty to assess their understanding of calculating the perimeter. Encourage students to double-check their work by verifying that they have included all sides in their calculations.
Differentiation
Support
- Offer additional practice with manipulatives, such as string or yarn, to physically measure and calculate perimeter.
- Provide step-by-step written guides for solving perimeter problems, breaking down the process into manageable steps.
- Pair struggling students with a peer tutor who can offer guidance and support during practice activities.
Extension
- Have students create their own rectilinear shapes and exchange them with a partner to calculate the perimeter.
- Challenge students to solve perimeter problems that include missing side lengths, requiring them to use reasoning skills.
- Provide more complex shapes and ask advanced students to decompose them into simpler shapes for easier calculation.
Assessment
Use the assessment section of the TeachTastic Worksheet Pack to formally evaluate students' mastery of calculating the perimeter of rectilinear shapes. This could include a mix of multiple-choice questions, short-answer problems, and word problems.
Review and closing
Review the key points of the lesson by summarizing how to calculate the perimeter of rectilinear shapes. Address any common mistakes or misconceptions you noticed during the lesson, and ensure all students understand how to approach perimeter problems. Invite students to ask any final questions and share their thoughts on the lesson.
Misconceptions
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Misconception: Students may think that the perimeter is the area inside the shape. Correction: Clarify that perimeter measures the distance around the shape, not the space inside.
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Misconception: Students might forget to include all sides when calculating the perimeter. Correction: Teach students to systematically check off each side as they add it to their total.
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Misconception: Students might incorrectly assume that all sides of a rectilinear shape are equal. Correction: Emphasize the importance of measuring or noting each side's length individually.