Mathematics

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50 mins

Teacher/Student led

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Learning Outcomes

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+80 XP

Teacher-led from the board. Pupils do not need a device, but can follow on one.

What you need:
IWB/Projector/Large Screen

Enlargement and Scale Factor

Learn how to enlarge shapes by multiplying each side by a scale factor, keeping the same proportions. Discover how to find the scale factor from an original and its enlarged image.

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1 Getting Started
2 Watch and Notice
3 Try It Together
4 Draw the Enlargement in Your Copy
5 Class Challenge
6 What Did We Notice?
7 What's Next
Pupil practice

Your turn

Your teacher is running this lesson on the board. Here is the part you can try yourself.

Your written work is on page 89

Transformation playground

1 - Getting Started ~5 mins

A 3 by 2 rectangle beside a 6 by 4 rectangle, the same shape at twice the size

Here is a small rectangle on the board, and beside it a bigger copy of exactly the same shape.

What got bigger? And by how much? Roughly how many times taller and wider is the second one?

👇 Mark your steps as done as you complete them.

+5 XP

2 - Watch and Notice ~9 mins

Watch these shapes on the grid, each with its enlargement drawn beside it. Look at the sides of each copy compared to the original.

A side of 3 squares becomes 6 when we multiply by 2 — not 5, as if we added 2. That multiplier is the scale factor: the number we multiply every side by.

The copy keeps its proportions. That means it stays the same shape: the angles do not change and every side grows together, so it is never squashed or stretched.

👇 Mark your steps as done as you complete them.

+10 XP

3 - Try It Together ~10 mins

Key point

Today we work through these enlargements together on the board. We start with a rectangle and enlarge it by a scale factor of 2, then the same shape by 3. Then we take a triangle and enlarge it by 2, and finally by 4 — and each time we check every side against the original before we agree.

Enlarge and check the sides

+15 XP

4 - Draw the Enlargement in Your Copy ~5 mins

COPYBOOK MOMENT

In your maths copy, draw a rectangle that is 2 cm by 3 cm. Then draw its enlargement by scale factor 3 beside it.

Label the new side lengths. Check each one by multiplying the original length by the scale factor.

+10 XP

Pupil practice

Module 8 · Location, Transformations and Scale Shape & Space

Lesson 96 · Enlargement and Scale Factor

Download Activity Book page (PDF)

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