How can you tell they’ve got it: Scale and similar shapes?

If they’ve got it, you’ll see things like: 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. Or just try it together: 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?

Mathematics Ratio & Proportion Ages 10–11

Scale and similar shapes

Your child can solve problems with scaled shapes and drawings. If 1 cm on a plan is 5 m, a 3.5 cm room is really 17.5 m long.

In curriculum terms

Solve problems involving similar shapes where the scale factor is known or can be found

Ages are typical, not deadlines — follow your child’s pace. How to help at home →

How to tell they’ve got it

Tick these off as you see them — no test required.

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

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Try this together

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?

Where this sits on the map

Stuck here? Check the skills it builds on first. Confident? Here’s what it unlocks.

Builds on

Percentagesages 9–11Similar shapes and scale requires 'scale', 'equivalent', and 'proportion' as defined terms

Classifying shapes by propertiesages 10–11Similarity requires understanding shape properties — equal angles, proportional sides

Ratio Problemsages 10–11Scale factor problems are a specific application of ratio/proportion

Bar Models for Ratiosages 9–12Scale factor problems for similar shapes can be represented as ratio bar models

Estimating answersages 9–10Scale factor problems often involve computing scaled lengths/perimeters/areas

Scale and similar shapesthis skill · ages 10–11

Unlocks

Scale and similar shapesages 11–13Scale diagrams and maps extend KS2 scale-factor work with similar shapes

Coordinatesages 12–14Enlargement extends KS2 scale factor work with similar shapes

Real-World Mathematical Modellingages 10–11Scale factor problems are key Y6 modelling contexts

solid = must come firstdashed = helps

Curriculum alignment

Where this fits in the official school curriculum — our best automated guess, not yet checked by a person.

Show candidate curriculum codes · 2 ACARA · 2 NSW · 2 VIC

Australian Curriculum v9 candidate

AC9M5M02low confidenceYear 5 · Measurement

solve practical problems involving the perimeter and area of regular and irregular shapes using appropriate metric units

AC9M6M02low confidenceYear 6 · Measurement

establish the formula for the area of a rectangle and use it to solve practical problems

NSW syllabus codes & stages only

MA3-2DS-03low confidenceMathematics K-10 · Stage 3

MA2-DATA-01low confidenceMathematics K-10 · Stage 2

Victorian Curriculum 2.0 codes & levels only

VC2M5M02low confidenceMathematics · Level 5 · Measurement strand

VC2M6M02low confidenceMathematics · Level 6 · Measurement strand

These are candidate alignments generated by semantic matching — machine-suggested and unreviewed (v0.1), not official or verified mappings. For official curriculum content see australiancurriculum.edu.au, curriculum.nsw.edu.au and f10.vcaa.vic.edu.au. Don’t rely on them for registration or compliance purposes.

Nearby on the map

Calculating Percentagesages 10–11 Ratio Problemsages 10–11 Understanding fractionsages 10–11 Bar Models for Ratiosages 9–12

All Ratio & Proportion skills →