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attention 2 learners

Circumference substituted for area

Uses 2πr while labelling the result as area.

Shared learning need

Distinguish what circumference and area measure, including their units.

Assessment question
A circle has a radius of 3 cm. What happens to its area when the radius is doubled? Explain your reasoning.
Selected response

Learner 04

1 / 2
“Use 2πr. With the new radius 6, the area is 2 × π × 6 = 12π cm².”
Final answer: 12π cm²
Reconstructed reasoning

Uses the circumference formula as an area formula.

high confidence
  1. Choose formula

    Selects 2πr.

  2. Substitute

    Correctly substitutes r = 6 into the chosen formula.

Evidence in the response

  • “Use 2πr.”
  • The numeric work is internally consistent for circumference.

Alternative hypothesis

The learner may have mislabelled circumference rather than confused the measures.

Teacher decision

Review this interpretation

Your judgement remains the final word for Learner 04.

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