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Grade 3 · unit review

Review: Distinguish Area from Perimeter

Count unit squares, add non-overlapping areas, and calculate boundaries and missing sides.

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Bring the unit skills together

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Unit review questions
1. A rectangle measures 7 units by 4 units. What is its area in square units?
Need a hint?
  • Area answers how much region is covered.
  • Report square units rather than ordinary length units.
2. A region has non-overlapping rectangular parts 6×4 and 2×3 units. What is its total area?
Need a hint?
  • Check that the stated parts cover the region completely.
  • Do not add overlapped areas without correcting the double count.
3. A rectangle is 9 cm long and 3 cm wide. What is its perimeter in centimeters?
Need a hint?
  • Trace the complete outside boundary once.
  • A rectangle has two sides of each given dimension.
4. A polygon perimeter is 38 cm. Its other sides are 8, 7, and 6 cm. What is the missing side length?
Need a hint?
  • Include each known side once in the subtotal.
  • Do not assume opposite sides match unless a shape definition supplies that fact.

The download contains your current choices and any checked feedback. Keep the separate transfer-task work in your own document; downloading its instructions does not mark it complete.

Use the skills in a new task

Compare rectangles 3 by 8 and 4 by 6. Find area and perimeter for both.

Work on paper or in your own document. Explain the choices you made.

  • Draw or label the numbers or shape features the task gives you.
  • Say why each calculation or shape choice follows the ideas in this unit.
  • Check that your answer fits the story or drawing in the task.
Compare with a model response

Both areas are 24 square units. Perimeters are 2(3+8)=22 units and 2(4+6)=20 units. Equal area does not force equal perimeter.

A different response can also meet the criteria. Compare the evidence and reasoning, rather than copying the wording.