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Relate area and volume under scaling

About 12 minutes · 3 reading + 9 practice and checks
Time includes reading, practice, and questions. Extra videos or further study are optional.
See this course’s project requirements

A geometry explanation board with angle deductions, congruence and similarity tests, a scale argument and a checked space-design decision.

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What to include

  • Keep every given and correspondence visible.
  • Show angle deductions with their reasons.
  • Distinguish congruence from similarity.
  • Check length, area and volume scale factors.
  • Write a final panel explanation and all changed-case responses.

Review and revise

Use these criteria to check your work and choose what to improve.

  • Method: applies the course-specific rules to the supplied cases with visible intermediate work.
  • Accuracy: results agree with the stated facts, units, boundaries and independent checks.
  • Reasoning: explains why the result follows and identifies a limitation or unresolved question.
  • Transfer: completes changed cases and revises the final project when a relevant assumption changes.
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Before you begin

The idea in everyday life

Case: rectangle 2 cm×3 cm and box 2 cm×3 cm×4 cm are enlarged with length factor 2.

The idea

Scaling every length by k multiplies area by k² and volume by k³. This differs from adding k to dimensions. Separate linear, area and volume units.

Follow along

Relate area and volume under scaling — worked practice

Scaling every length by k multiplies area by k² and volume by k³. This differs from adding k to dimensions. Separate linear, area and volume units.

Case: rectangle 2 cm×3 cm and box 2 cm×3 cm×4 cm are enlarged with length factor 2.

Case information

Paste at A1.

ARecordBGiven
Original caseCase: rectangle 2 cm×3 cm and box 2 cm×3 cm×4 cm are enlarged with length factor 2.

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  1. 1. 1. Baseline

    Calculate original area and volume.

    You should see: Area 6cm²; volume 24cm³.

  2. 2. 2. Scale lengths

    Double each dimension.

    You should see: Rectangle 4×6; box 4×6×8 cm.

  3. 3. 3. Calculate

    Find enlarged area and volume.

    You should see: Area 24cm²; volume 192cm³.

  4. 4. 4. Compare factors

    Divide enlarged by original.

    You should see: Area factor 4; volume factor 8, not factor 2.

Now change one thing

A rectangle with area 5cm² is enlarged with length factor 3. Find its new area.

Your work

What to finish

A dimension, area and volume scaling comparison with units.

Common mistake

Watch for this

Length×width gains 2×2=4.

How can I tell I understand it?

Explain why doubling all lengths multiplies area by four and volume by eight.

Try 3 questions

Quick knowledge check

Answer all 3 questions. Get at least 2 right and the lesson completes automatically.

Not yet passed

You’ll get an explanation for each answer. Signed in? Your results save to your account.

1A cube volume 10cm³ is scaled in length by 2. What is the new volume?
2Which unit represents area?
3Why is doubling all dimensions not merely doubling area?
0 of 3 answeredApply the lesson to a short question, then review the explanation.
5
Finish this lesson

Pass the check. We’ll save the progress.

Answer all 3 questions above and get at least 2 right. You can review the explanations and try again.

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Tools, templates, and lesson sources

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Sources and further reading

Explore the references behind this lesson.

OpenStax: volume and surface area
Source & access notes · checked 2026-10-01

Web open/search showed the official page, its topic heading and relevant concept description. This is a content/source check, not a provider endorsement.

Access: Official page retrieved with the web reader on 2026-10-01; interactive tools and videos were not certified by retrieval.

Reuse: Original fictional teaching cases, calculations, questions and examples; link and short factual paraphrase only. No copied source exercises or illustrations.

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