Reach for the Star

Perimeter and compound area

Pearson Edexcel GCSE Mathematics 1MA1 · Foundation and Higher · L033 · Review v0.9

Your learning journey

Calculate perimeters and areas of compound rectilinear shapes, triangles, parallelograms and trapezia with correct units.

Follow the task-specific calculator guidance in Apply. Keyboard - means the same as −. Attempt before opening a scaffold or intentional practice explanation.

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Ready.

Connect & Check

Perimeter: total boundary length. Area: surface coverage. Perpendicular height: shortest distance between parallel bases. Compound shape: shape assembled from familiar parts.

Intentional practice feedback after your attempt

20 cm.

2(6+4).

Intentional practice feedback after your attempt

24 cm².

6×4.

Intentional practice feedback after your attempt

100 mm².

10×10, not 10.

Share

In pairs, predict the first step and compare your reasons before reading the worked solution: D1 Model: rectangle 8×5 cm with a 3×2 cm corner removed has area 40−6=34 cm². Now 10×6 cm minus a 4×2 cm corner.

Present

A rectangle contains length×width unit squares. A triangle is half a parallelogram, so area=base×perpendicular height÷2. Shearing a parallelogram preserves area. Two matching trapezia make a parallelogram, giving area=(a+b)h÷2 for parallel sides a,b. Split compound shapes without overlap; internal cut lines do not count in the perimeter.

Label missing lengths. Trace the outer boundary for perimeter. For area, choose non-overlapping pieces or subtract a cut-out. State square units. Estimate and use a second partition to check.

Perimeter and compound area teaching diagram; not to scale10 cm overall6 cm4 cm2 cmRight-angled corner cut-outArea: subtract rectangles.Perimeter: trace boundary.Teaching sketch • not to scale
Teaching sketch: not to scale. Use the separate practical sheet for drawing tasks. Describe your reasoning here; your teacher reviews the paper drawing.
Optional scaffold

Subtract removed area.

Intentional practice feedback after your attempt

52 cm².

60−8.

Optional scaffold

Height must be perpendicular.

Intentional practice feedback after your attempt

35 cm².

10×7÷2.

Optional scaffold

Sloping edge is not height.

Intentional practice feedback after your attempt

45 cm².

9×5.

Optional scaffold

Add only the parallel sides.

Intentional practice feedback after your attempt

28 cm².

(5+9)×4÷2.

Apply

Optional scaffold

Sketch the bounding parallelogram.

Intentional practice feedback after your attempt

40 cm² and 20 cm².

Triangle is half for equal base and height.

Intentional practice feedback after your attempt

52 cm²; 32 cm.

Removed boundary lengths are replaced by equal inset lengths; trace all six sides.

Intentional practice feedback after your attempt

34 m²; 68 tiles.

Divide area by coverage per tile.

Optional check: (5+9)×4÷2=28. Enter brackets round the sum. Estimate first; a triangle with the same base and height has half the parallelogram area.

Apply and extend

Intentional practice feedback after your attempt

4×4 gives perimeter 16 area16; 6×2 gives perimeter16 area12.

Same boundary length does not fix area.

Intentional practice feedback after your attempt

False: perimeter stays 32 cm; removed 4+2 is replaced by inset 4+2.

This refers to a corner cut, not any hole or notch.

Access, Scaffold, Core and Stretch support the same goal. Stretch deepens reasoning for either qualification tier.

Recall & Review

Retrieval without notes

Six retrieval points. Enter a number, decimal, fraction such as 3/2, or mixed number such as 1 1/2. Equivalent numeric values are accepted. Unsupported notation goes to teacher review. For rounding, also communicate the requested accuracy in written work; numerical scoring cannot judge significant trailing zeros.







Not checked.

Independent exit evidence

P1–P2: five minutes, no notes, 4 marks. Your teacher reviews working and explanations. Full assessment solutions are not embedded.

Recall & Review and prepare

A circle circumference is 2πr and area is πr². An arc or sector represents a fraction of the whole circle determined by its central angle divided by 360°.

Retrieve F1 again in one week. Bring your working and one question.

Your progress summary

Completion records attempts, not mastery. Retrieval points describe the latest checked attempt. Your teacher reviews P1–P2 separately and checks retained understanding after a delay.

Restore a backup

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Optional extension activities

Allow 10–15 minutes if the main practice is secure. Show your method, explain a check and justify your conclusion.

Stretch

Reveal a worked check after attempting

Area=96−6=90 cm²; perimeter remains 40 cm for a corner notch.

Deep challenge

Reveal a worked check after attempting

No. A 6×6 square has perimeter 24 cm; a 4×9 rectangle has perimeter 26 cm.

Recall & Review: feedback and extension integration

Lesson L033: Perimeter and compound area

Objective: Calculate perimeters and areas of compound rectilinear shapes, triangles, parallelograms and trapezia with correct units.

60-minute structure: 0-7 Connect & Check; 7-14 Share; 14-25 Present/model; 25-44 Apply route choice/practice; 44-52 independent exam-style check; 52-60 Recall & Review, WWW/EBI and next step.

What Went Well (WWW)

I selected the correct geometric fact, theorem, formula or transformation and used a clear diagram with appropriate labels and units.

Even Better If (EBI)

I will name the fact or theorem, show the substitution or construction step and check whether the size, direction and units of the result are reasonable.

Stretch and deep challenge

Stretch: A rectangle 12 cm by 8 cm has a 3 cm by 2 cm corner cut out. Find area and perimeter.

Deep challenge: Two shapes each have area 36 cm². Must their perimeters be equal? Give a counterexample.