Lesson Plan
Scale Up! Scale Down!
Students will be able to apply a given scale factor to a 2D shape and draw the resulting scaled copy, understanding how dimensions change proportionally.
Understanding scale factors helps us make sense of maps, blueprints, models, and even digital image resizing. It teaches us how things can grow or shrink while keeping their original proportions, a key skill for many real-world applications.
Audience
7th Grade
Time
15 minutes
Approach
Direct instruction, guided practice, and independent worksheet application.
Materials
Whiteboard or Projector, Markers or Pens, Scale Up! Scale Down! Worksheet, and Rulers (optional)
Prep
Preparation
5 minutes
- Review the Scale Up! Scale Down! Worksheet and be familiar with the examples and instructions.
* Prepare a whiteboard or projector to display the initial shape and demonstrate applying a scale factor.
* Ensure copies of the Scale Up! Scale Down! Worksheet are ready for each student.
Step 1
Introduction to Scale Factors (5 minutes)
5 minutes
- Engage: Begin by asking students if they've ever seen a map or a toy model. How do these items represent much larger (or smaller) real-life objects?
* Define: Explain that a 'scale factor' is a number that tells us how much to multiply the dimensions of an object by to enlarge or reduce it. If the scale factor is greater than 1, the object gets bigger. If it's between 0 and 1, the object gets smaller.
* Demonstrate: On the whiteboard/projector, draw a simple rectangle (e.g., 2 units by 3 units). Ask students, "If our scale factor is 2, what would the new dimensions be?" Guide them to understand that each side length is multiplied by 2 (4 units by 6 units). Draw the new rectangle.
Step 2
Worksheet Application (8 minutes)
8 minutes
- Distribute: Hand out the Scale Up! Scale Down! Worksheet to each student.
* Explain: Clearly state the instructions: Students will be given an original shape and a scale factor. Their task is to apply the scale factor to each dimension and then draw the new scaled copy of the shape.
* Guided Practice: Work through the first example on the worksheet together as a class to ensure understanding.
* Independent Work: Allow students to complete the remaining problems independently. Circulate around the room to provide support and answer questions.
Step 3
Wrap-Up (2 minutes)
2 minutes
- Review: Briefly review one or two of the problems from the Scale Up! Scale Down! Worksheet as a class, focusing on common challenges or misconceptions.
* Connect: Ask students to share one place in the real world where they might see scale factors being used (e.g., architecture, photography, video games).
Slide Deck
Welcome to Scale Up! Scale Down!
Have you ever seen a model car or a map? How do these represent real things?
Greet students and start with an engaging question to activate prior knowledge about real-world scaling.
What's a Scale Factor?
A scale factor tells us how much to grow or shrink a shape!
- Scale Factor > 1: Shape gets BIGGER!
- Scale Factor < 1 (but > 0): Shape gets SMALLER!
Introduce the concept of a scale factor. Emphasize that it's a number we multiply by to change size proportionally. Explain greater than 1 means bigger, less than 1 means smaller.
Let's Try It! (Example)
Original Rectangle: 2 units x 3 units
Scale Factor: 2
What are the new dimensions? How do we find them?
Demonstrate a simple example on the board or projector. Draw a 2x3 rectangle and then its scaled copy with a factor of 2. Talk through multiplying each side.
Your Turn! The Worksheet Challenge!
You'll get a shape and a scale factor. Your mission:
- Multiply each side by the scale factor.
- Draw the new scaled copy!
We'll do the first one together!
Explain that students will now work on a worksheet. Go over the instructions for the worksheet and walk them through the first problem together.
Time to Get Scaling!
Work through the rest of your Scale Up! Scale Down! Worksheet independently.
Remember: Every side length changes by the scale factor!
Encourage students to work independently. Remind them to think carefully about how the scale factor affects the size. Circulate and assist.
Real-World Scaling!
Where do you see scale factors used in the world around you?
- Maps
- Models (cars, airplanes, buildings)
- Blueprints
- Computer Graphics
Bring the class back together. Quickly review one problem and ask students for real-world examples of scale factors.
Worksheet
Scale Up! Scale Down! Worksheet
Instructions: For each problem, you are given an original shape and a scale factor. Apply the scale factor to the dimensions of the original shape, then draw the new scaled copy in the space provided. Make sure your drawing is proportional to the original and clearly label the new side lengths.
Problem 1
Original Shape: Rectangle
Original Dimensions: Length = 4 units, Width = 2 units
Scale Factor: 2
New Dimensions:
Draw the Scaled Copy Here:
Problem 2
Original Shape: Square
Original Dimensions: Side = 3 units
Scale Factor: 1/3
New Dimensions:
Draw the Scaled Copy Here:
Problem 3
Original Shape: Triangle (Right-angled)
Original Dimensions: Base = 3 units, Height = 4 units
Scale Factor: 1.5
New Dimensions:
Draw the Scaled Copy Here:
Problem 4
Original Shape: Rectangle
Original Dimensions: Length = 6 units, Width = 3 units
Scale Factor: 0.5
New Dimensions:
Draw the Scaled Copy Here:
Challenge Problem (Optional)
Original Shape: A simple house outline (Rectangle for base, Triangle for roof)
Original Dimensions: Base Rectangle (4 units x 3 units), Roof Triangle (Base 4 units, Height 2 units)
Scale Factor: 2
New Dimensions:
Draw the Scaled Copy Here:
Answer Key
Scale Up! Scale Down! Answer Key
Instructions: This answer key provides the correct scaled dimensions and a description of the scaled copy for each problem on the Scale Up! Scale Down! Worksheet.
Problem 1
Original Shape: Rectangle
Original Dimensions: Length = 4 units, Width = 2 units
Scale Factor: 2
Thought Process: To find the new dimensions, multiply each original dimension by the scale factor.
New Length = 4 units * 2 = 8 units
New Width = 2 units * 2 = 4 units
New Dimensions: Length = 8 units, Width = 4 units
Description of Scaled Copy: A larger rectangle with length 8 units and width 4 units.
Problem 2
Original Shape: Square
Original Dimensions: Side = 3 units
Scale Factor: 1/3
Thought Process: To find the new dimensions, multiply each original dimension by the scale factor.
New Side = 3 units * (1/3) = 1 unit
New Dimensions: Side = 1 unit
Description of Scaled Copy: A smaller square with side length 1 unit.
Problem 3
Original Shape: Triangle (Right-angled)
Original Dimensions: Base = 3 units, Height = 4 units
Scale Factor: 1.5
Thought Process: To find the new dimensions, multiply each original dimension by the scale factor.
New Base = 3 units * 1.5 = 4.5 units
New Height = 4 units * 1.5 = 6 units
New Dimensions: Base = 4.5 units, Height = 6 units
Description of Scaled Copy: A larger right-angled triangle with base 4.5 units and height 6 units. The hypotenuse would also be scaled by 1.5.
Problem 4
Original Shape: Rectangle
Original Dimensions: Length = 6 units, Width = 3 units
Scale Factor: 0.5
Thought Process: To find the new dimensions, multiply each original dimension by the scale factor.
New Length = 6 units * 0.5 = 3 units
New Width = 3 units * 0.5 = 1.5 units
New Dimensions: Length = 3 units, Width = 1.5 units
Description of Scaled Copy: A smaller rectangle with length 3 units and width 1.5 units.
Challenge Problem (Optional)
Original Shape: A simple house outline (Rectangle for base, Triangle for roof)
Original Dimensions: Base Rectangle (4 units x 3 units), Roof Triangle (Base 4 units, Height 2 units)
Scale Factor: 2
Thought Process: Apply the scale factor to all dimensions of both the rectangle and the triangle.
Rectangle New Length = 4 units * 2 = 8 units
Rectangle New Width = 3 units * 2 = 6 units
Triangle New Base = 4 units * 2 = 8 units
Triangle New Height = 2 units * 2 = 4 units
New Dimensions: Base Rectangle (8 units x 6 units), Roof Triangle (Base 8 units, Height 4 units)
Description of Scaled Copy: A larger house outline where the base is a rectangle measuring 8 units by 6 units, and the roof is a triangle with a base of 8 units (matching the rectangle's length) and a height of 4 units.