Scale and similar shapes
Solve problems involving similar shapes where the scale factor is known or can be found
Lesson
Set out your lesson
“Scale and similar shapes means practising the idea at the table with counters or paper models and one clear check. We will demo once, then your child tries.”
Bring to the table
- Paper shapes or a ruler and pencil
- Shape name cards
Extra for the adult
Worked example. A rectangle has four right angles. Naming the property is the check.
Optional challenge. For Scale and similar shapes, add one harder example after success.
What to notice. Keep one parent note: examples tried; results; support used. This session samples Scale and similar shapes, not mastery.
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Teaching approaches
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1 approach
Scale and similar shapes means practising the idea at the table with counters or paper models and one clear check. We will demo once, then your child tries.
Materials: Paper shapes or a ruler and pencil; Shape name cards. Adult traces or shows one shape and names a property (sides/angles). Child identifies three shapes or measures one simple property and records it. Done: three correct shape/property responses. Stop after the fresh check; keep optional challenge for another day.
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Practice this concept
Start practiceScale and similar shapes practice
Practice key ideas from Scale and similar shapes.
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Learning resources
Extra practice links — they do not replace Gakuva’s teaching approach.
Illustrative Mathematics · Practice link — not the full lesson
Overlapping Squares
Before you open · source notes
Overlapping Squares supports scale thinking with similar square regions. Not every perspective-drawing course.
Free, no sign-in. A teacher solution is on the same page, so use the student view with your child.
Before you openAsk the learner how a scale factor changes a square side or area.
Opening this link does not save learning or assess mastery.
Source, access and review notes
Public Illustrative Mathematics task page. The .html address responds HTTP 308 to this URL. An anonymous GET of this URL on 2026-11-12 returned HTTP 200 with no login or payment prompt. Where a teacher solution is present, it is on the same page as the student task; this check did not find a separate locked student view. An adult can use the student view section and should not read a solution aloud. Advertising was not observed in the fetched HTML text; that is not a browser, device, or ad-free guarantee. This is a paper or discussion task, not an automatically marked interactive game. Opening the link does not save practice or assess mastery. Diagrams on the page use missing or filename-only alt text, so they are not an accessible image equivalent. Accessibility still depends on an adult describing the picture.
Illustrative Mathematics. “Overlapping Squares.” Licensed CC BY-NC-SA 4.0. External task; Gakuva does not copy, host, embed, or redistribute it.
CC BY-NC-SA 4.0 — link only
Check understanding
- Find the missing side of a similar rectangle given a scale factor of 3
- Determine the scale factor between two similar triangles from given side lengths
- Use a scale factor to enlarge or reduce a shape and verify that all sides are in the same ratio
“If your child has a scale drawing where 1 cm represents 5 m, and a room measures 3.5 cm on the plan, can they work out the real length of the room?”
Curriculum record
- Type
- Procedural
- Subject
- Mathematics
- Domain
- Ratio & Proportion
- Age range
- Ages 10–13
Standards