How can you tell they’ve got it: Perimeters of polygons?

If they’ve got it, you’ll see things like: Calculate the perimeter of a rectangle with sides 8 cm and 5 cm; Find the missing side of a pentagon with perimeter 30 cm and four known sides; Draw two rectangles both with perimeter 24 cm but different areas. Or just try it together: If a rectangle has a perimeter of 24 cm and one side is 8 cm, can your child work out the length of the other side — without drawing it?

Mathematics Measurement Ages 8–9

Perimeters of polygons

Your child can solve perimeter problems. Given a rectangle's perimeter of 24 cm and one side of 8 cm, they find the other side is 4 cm.

In curriculum terms

Solve problems involving perimeters of polygons: find perimeter from side lengths, find an unknown side length, and explore rectangles with same perimeter but different areas (or vice versa)

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.

Calculate the perimeter of a rectangle with sides 8 cm and 5 cm
Find the missing side of a pentagon with perimeter 30 cm and four known sides
Draw two rectangles both with perimeter 24 cm but different areas

🖨 Print this page to keep the checklist — it prints beautifully.

Try this together

If a rectangle has a perimeter of 24 cm and one side is 8 cm, can your child work out the length of the other side — without drawing it?

Where this sits on the map

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

Builds on

Measuring Perimetersages 7–8Measuring perimeter of simple shapes is prerequisite to perimeter problem solving

Understanding anglesages 8–9Area of rectangles supports exploring same-perimeter-different-area relationships

Perimeters of polygonsthis skill · ages 8–9

Unlocks

Estimating answersages 9–10Y4 perimeter problems are prerequisite to applying perimeter formula

Perimeter of Compound Shapesages 9–10Y4 perimeter of polygons is prerequisite to composite rectilinear perimeter

Multi-Step Problem Solvingages 8–9Perimeter problems exercise multi-step problem solving at age 8-9

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

AC9M5M02medium confidenceYear 5 · Measurement

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

AC9M4M02low confidenceYear 4 · Measurement

recognise ways of measuring and approximating the perimeter and area of shapes and enclosed spaces, using appropriate formal and informal units

NSW syllabus codes & stages only

MA3-GM-02medium confidenceMathematics K-10 · Stage 3

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

Victorian Curriculum 2.0 codes & levels only

VC2M5M02medium confidenceMathematics · Level 5 · Measurement strand

VC2M4M02low confidenceMathematics · Level 4 · 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

12-hour and 24-hour timeages 8–9 Areaages 8–9 Area and the distributive propertyages 8–9 Area by Tilingages 8–9

All Measurement skills →