Walking Around Shapes: Discovering Perimeter!

Mathematics Grades 4th Grade 2:02 Video
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Lesson Description

Learn how to find the perimeter of different shapes by adding up the lengths of their sides. Get ready to walk around some shapes!

Video Resource

Perimeter of a shape | Measurement | Pre-Algebra | Khan Academy

Khan Academy

Duration: 2:02
Watch on YouTube

Key Concepts

  • Perimeter as the distance around a shape
  • Adding side lengths to find perimeter
  • Perimeter of regular shapes using multiplication

Learning Objectives

  • Students will be able to define perimeter as the total distance around a shape.
  • Students will be able to calculate the perimeter of various shapes by adding the lengths of their sides.
  • Students will be able to calculate the perimeter of regular polygons using multiplication.

Educator Instructions

  • Introduction (5 mins)
    Begin by asking students what they know about shapes. Introduce the word 'perimeter' and explain that it means the distance around the outside of a shape, like walking around the edge of a park or a playground.
  • Video Viewing (7 mins)
    Play the Khan Academy video 'Perimeter of a shape'. Encourage students to pay attention to how the perimeter is calculated in the video using addition.
  • Guided Practice (10 mins)
    Work through examples similar to those in the video on the board. Start with simple shapes like squares and rectangles, then move on to more irregular shapes. Emphasize the importance of adding all the sides.
  • Independent Practice (10 mins)
    Provide students with a worksheet containing various shapes and their side lengths. Have them calculate the perimeter of each shape independently. Provide assistance as needed.
  • Wrap-up (3 mins)
    Review the key concepts and answer any remaining questions. Preview the idea of using multiplication to find the perimeter of regular polygons.

Interactive Exercises

  • Shape Scavenger Hunt
    Have students find objects in the classroom with different shapes (e.g., books, tables, posters). Ask them to estimate the side lengths and then calculate the approximate perimeter of the object.
  • Perimeter Puzzles
    Provide students with puzzles where they have to find the missing side length of a shape, given its perimeter and other side lengths. This reinforces the concept of perimeter and requires problem-solving skills.

Discussion Questions

  • What is perimeter?
  • How do you find the perimeter of a shape?
  • What is a regular shape, and how does that help us find the perimeter faster?

Skills Developed

  • Addition
  • Problem-solving
  • Measurement

Multiple Choice Questions

Question 1:

What is the perimeter of a shape?

Correct Answer: The distance around the shape

Question 2:

A rectangle has sides of 5 cm and 3 cm. What is its perimeter?

Correct Answer: 16 cm

Question 3:

What do you do to find the perimeter of a shape?

Correct Answer: Add all the sides

Question 4:

A square has sides that are all 4 inches long. What is the perimeter?

Correct Answer: 16 inches

Question 5:

What is a shape called when all of its sides are the same length?

Correct Answer: Regular Shape

Question 6:

A regular pentagon has sides of 2 meters each. What is its perimeter?

Correct Answer: 10 meters

Question 7:

If a shape has sides of 2 cm, 3 cm, 4 cm, and 5 cm, what is the perimeter?

Correct Answer: 14 cm

Question 8:

What unit do we use to measure perimeter?

Correct Answer: Centimeters

Question 9:

Which shape is best described by using multiplication to find perimeter?

Correct Answer: Square

Question 10:

What do we call the outside boundary of a shape?

Correct Answer: Perimeter

Fill in the Blank Questions

Question 1:

The distance around a shape is called its _________.

Correct Answer: perimeter

Question 2:

To find the perimeter, you must ______ all the sides.

Correct Answer: add

Question 3:

A square has 4 sides that are all the ______ length.

Correct Answer: same

Question 4:

A shape where all sides are the same length is a ______ shape.

Correct Answer: regular

Question 5:

A rectangle has two sides that are 6 inches and two sides that are 3 inches. Its perimeter is ______ inches.

Correct Answer: 18

Question 6:

If each side of a pentagon is 5 cm, the perimeter of the pentagon is ______ cm.

Correct Answer: 25

Question 7:

We measure perimeter in units like centimeters or ________.

Correct Answer: meters

Question 8:

The opposite of perimeter is the measurement of the ______ inside a shape.

Correct Answer: area

Question 9:

If a triangle has sides of 4, 5, and 6, its perimeter is _______.

Correct Answer: 15

Question 10:

When finding the perimeter of a square you can use multiplication or repeated _______.

Correct Answer: addition

Educational Standards

4.GM.3:Determine elapsed time and convert between units of time. 4.N.2:Solve real-world and mathematical problems using multiplication and division. 4.GM.2:Recognize and measure attributes in real-world and mathematical situations using various tools.

Teaching Materials

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