AC9M5M02 • Year 5 Maths

AC9M5M02: Solve practical problems involving the perimeter and area of regular and irregular shapes using appropriate metric units

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

Topic GuideClassroom ViewWorksheetPracticeTest
What students learn in AC9M5M02

Students distinguish boundary length from surface coverage, calculate regular shapes, decompose composite regions and approximate irregular spaces with stated assumptions and metric units.

Perimeter uses linear units around a boundary; area uses square units covering a region.

For area, subtract the missing rectangle. For perimeter, trace only the outer boundary and include the new internal corner edges.

An approximation is defensible when the grid scale, partial-square rule and uncertainty are stated.

Learning routine: Represent → Reason → Calculate → Interpret → Verify

Success looks like

  • Represent accurately
  • Explain the relationship
  • Choose a suitable method or unit
  • Apply in context
  • Check and justify
Key vocabulary
perimeter
distance around a boundary
area
surface covered in square units
decomposition
breaking a shape into simpler parts
Concept models and worked thinking

Calculate a composite L-shaped garden

decompositiondimensionsarealarge rectangle8 m × 6 m48 m²removed rectangle3 m × 2 m6 m²garden area48 − 642 m²perimetersum outer edges24 m

For area, subtract the missing rectangle. For perimeter, trace only the outer boundary and include the new internal corner edges.

  1. Read every label and identify the quantities, parts or evidence.
  2. Explain the relationship shown—not just the final answer.
  3. Check the conclusion against the original question and units.

Approximate an irregular area on a grid

whole squarescount exactly
partial squarescombine halves or use a consistent threshold
perimetertrace boundary and estimate curved segments
reportstate approximately and give unit/range

An approximation is defensible when the grid scale, partial-square rule and uncertainty are stated.

Now transfer the same relationship to a new situation and justify the result with precise vocabulary.

Curriculum coverage and elaborations

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

  • E1: investigating problem situations involving perimeter; for example, “How many metres of fencing are required around a paddock, or around a festival event?”
  • E2: using efficient ways to calculate the perimeters of rectangles, such as adding the length and width together and doubling the result
  • E3: solving measurement problems, such as “How much carpet would be needed to cover the entire floor of the classroom”, using square metre templates to directly measure the floor space
  • E4: creating a model of a permaculture garden, dividing the area up to provide the most efficient use of space for gardens and walkways, labelling the measure of each area, and calculating the amount of resources needed; for example, compost to cover the vegetable garden
  • E5: using a physical or a virtual “geoboard app” to recognise the relationship between area and perimeter and solve problems; for example, investigating what is the largest and what is the smallest area that has the same perimeter
  • E6: exploring the designs of fishing nets and dwellings of First Nations Australians, investigating the perimeter, area and purpose of the shapes within the designs
Guided learning activities

1. Model and annotate

Represent perimeter and area of regular and irregular shapes and label the relationship or measurement being used.

decompositiondimensionsarealarge rectangle8 m × 6 m48 m²removed rectangle3 m × 2 m6 m²garden area48 − 642 m²perimetersum outer edges24 m

2. Strategy or instrument comparison

Compare two valid methods or tools and justify which better suits the numbers, attribute or purpose.

whole squarescount exactly
partial squarescombine halves or use a consistent threshold
perimetertrace boundary and estimate curved segments
reportstate approximately and give unit/range

3. Transfer and verify

Apply the concept to an unfamiliar example, state units or conditions and verify independently.

Find area of an L-shape.Trace a composite perimeter.Choose m² for a garden.Approximate partial squares.
Revision Notes

Core idea: Perimeter uses linear units around a boundary; area uses square units covering a region.

Remember

  • Represent accurately
  • Explain the relationship
  • Choose a suitable method or unit
  • Apply in context
  • Check and justify

Important questions

  • Find area of an L-shape. Explain using the model or evidence above.
  • Trace a composite perimeter. Explain using the model or evidence above.
  • Choose m² for a garden. Explain using the model or evidence above.
  • Approximate partial squares. Explain using the model or evidence above.
  • Explain perimeter versus area. Explain using the model or evidence above.
How to use this unit

Learn from the Topic Guide and fixed Teacher Slides, complete the Practice Sheet, use Practice for supported feedback, then take the Test when ready.

AC9M5M02 Teacher Slides

Project the fixed branded slide deck one slide at a time.

Open Classroom View
Common misconceptions
  • Interior grid lines included in perimeter — Trace only the external boundary.
  • Linear units used for area — Write cm² or m².
  • Missing rectangle added instead of removed — Check the physical region represented.
  • Approximation reported as exact — State method and uncertainty.
🎥 Optional Video Lesson

The SkillrHub lesson remains the primary learning resource. This optional video reinforces the explanation; you can complete the lesson and practice without watching.

Back to the lesson

Before you watch:

  • Pause after each worked example.
  • Try the examples yourself.
  • Return to the SkillrHub lesson before continuing.
Recommended: Perimeter

Math Antics — Find the distance around a shape and distinguish it from the area inside.

As you watch: Which lengths must be counted to find the entire boundary?

Load video player Loads YouTube in this lesson. See the video notice below.

Try it: Draw a stepped garden outline on square paper and calculate its perimeter in metres.

Video unavailable, inaccurate or unsuitable for this year? Report a video problem to SkillrHub by email. You can continue with the written lesson and practice resources.

Another explanation: Area

Math Antics — Connect area with the number of square units needed to cover a shape.

As you watch: Why are area units square units rather than ordinary length units?

Load video player Loads YouTube in this lesson. See the video notice below.

Try it: Split a stepped floor plan into rectangles and calculate its area in square metres without overlaps.

Video unavailable, inaccurate or unsuitable for this year? Report a video problem to SkillrHub by email. You can continue with the written lesson and practice resources.

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Curriculum equivalents: Victoria, NSW and international

Curriculum equivalents for Solve practical problems involving the perimeter and area of regular...

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

These references identify matching or closely related learning. Curriculum sequence, terminology and depth vary, so teachers should use the mapped skill and lesson difficulty to confirm suitability.

RegionCurriculum frameworkClosest level or code
AustraliaAustralian Curriculum v9.0AC9M5M02 · Year 5
VictoriaVictorian Curriculum F–10 Version 2.0 — MathematicsVC2M5M02 · Level 5
New South WalesNSW Mathematics K–10 Syllabus (2022)MA3-2DS-02 + MA3-2DS-03 · Stage 3
United States (USA)Common Core State Standards for MathematicsGrade 5
Canada (Ontario)Ontario Curriculum — MathematicsGrade 5
United Kingdom (England)National Curriculum in England — MathematicsYear 6, Key Stage 2
IndiaNCERT / CBSE — MathematicsClass 5

Australian Curriculum v9.0 is the canonical source for this SkillrHub lesson. Victoria and NSW entries name the closest published state codes or outcomes; international entries are planning references rather than claims of identical curricula.

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Official curriculum reference

Australian Curriculum Version 9.0

Related Year 5 Maths topics

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