Walking Around Shapes: Discovering Perimeter!
Lesson Description
Video Resource
Key Concepts
- Perimeter is the distance around a shape.
- Perimeter is measured in units of length (e.g., cm, m, inches).
- To find the perimeter of a polygon, add the lengths of all its sides.
- For regular polygons (all sides equal), you can multiply the side length by the number of sides.
Learning Objectives
- Students will be able to define perimeter in their own words.
- Students will be able to calculate the perimeter of various polygons by adding the lengths of their sides.
- Students will be able to use multiplication as a shortcut to find the perimeter of regular polygons.
- Students will be able to identify the correct units of measurement for perimeter.
Educator Instructions
- Introduction (5 mins)
Begin by asking students what they know about shapes. Then, introduce the term 'perimeter' as the distance around a shape. Show real-world examples like the perimeter of a desk or a picture frame. - Video Viewing (10 mins)
Play the Math Antics - Perimeter video (https://www.youtube.com/watch?v=AAY1bsazcgM). Encourage students to take notes on key definitions and examples. - Guided Practice (15 mins)
Work through several example problems on the board, demonstrating how to calculate the perimeter of different polygons (triangle, rectangle, regular hexagon, irregular polygon). Emphasize the importance of including units in the answer. For irregular polygons, model how to find missing side lengths. - Independent Practice (15 mins)
Provide students with a worksheet containing various polygon shapes and side lengths. Have them calculate the perimeter of each shape independently. Circulate the room to provide assistance as needed. - Review and Wrap-up (5 mins)
Review the key concepts of perimeter and address any remaining questions. Discuss real-world applications of perimeter, such as fencing a garden or measuring a room for carpeting.
Interactive Exercises
- Shape Scavenger Hunt
Have students find objects in the classroom that are shaped like polygons. They should then measure the sides of the object and calculate its perimeter. - Perimeter Puzzles
Provide students with puzzles where they are given the perimeter of a shape and some side lengths, and they need to determine the missing side length(s).
Discussion Questions
- What is perimeter in your own words?
- Why is it important to include units when stating the perimeter of a shape?
- How is finding the perimeter of a regular polygon different from finding the perimeter of an irregular polygon?
- Can you think of any real-world examples where knowing the perimeter of something would be useful?
Skills Developed
- Problem-solving
- Measurement
- Addition
- Multiplication
- Critical Thinking
- Attention to detail
Multiple Choice Questions
Question 1:
What does perimeter mean?
Correct Answer: The distance around a shape
Question 2:
What unit of measurement would you use for perimeter?
Correct Answer: Inches
Question 3:
A square has sides that are 5 cm long. What is the perimeter of the square?
Correct Answer: 20 cm
Question 4:
A triangle has sides of 3 inches, 4 inches, and 5 inches. What is its perimeter?
Correct Answer: 12 inches
Question 5:
What is a 'regular' polygon?
Correct Answer: A shape with all sides the same length
Question 6:
How can you find the perimeter of a regular hexagon with each side measuring 2 inches?
Correct Answer: Multiply 6 x 2
Question 7:
A rectangle has two sides that are 8 meters long and two sides that are 3 meters long. What is the perimeter?
Correct Answer: 22 meters
Question 8:
If you know the perimeter of a square is 36 inches, how long is each side?
Correct Answer: 9 inches
Question 9:
You are building a fence around your garden. Knowing the ___________ will help you know how much fencing to buy.
Correct Answer: Perimeter
Question 10:
Which shape has the largest perimeter, assuming all sides are equal? A square with sides of 4 cm, or a pentagon with sides of 3 cm?
Correct Answer: Square
Fill in the Blank Questions
Question 1:
The distance around a shape is called the ___________.
Correct Answer: perimeter
Question 2:
Perimeter is always measured in units of ___________.
Correct Answer: length
Question 3:
To find the perimeter of a polygon, you ___________ the lengths of all the sides.
Correct Answer: add
Question 4:
A regular polygon has all sides of the same ___________.
Correct Answer: length
Question 5:
A rectangle has 2 long sides and 2 short sides. To find the perimeter, you add all ___________ sides.
Correct Answer: four
Question 6:
If a shape has sides of 6 cm, 6 cm, 4 cm, and 4 cm, the perimeter is ___________ cm.
Correct Answer: 20
Question 7:
Multiplication can be used as a shortcut to find the perimeter of ___________ polygons.
Correct Answer: regular
Question 8:
A regular pentagon has 5 sides. If each side is 2 inches, the perimeter is ___________ inches.
Correct Answer: 10
Question 9:
If you are missing a side length on a shape, you need to use the information you __________ to find the missing length.
Correct Answer: know
Question 10:
Always remember to write down the ___________ when you find the perimeter!
Correct Answer: units
Educational Standards
Teaching Materials
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