AI generatedGeometry and measuresKey Stage 3

Finding a missing length from an area

Finding a missing length from an area.

  • Identify the relevant shape or angle fact before calculating.
  • Use the labelled information and show each rearrangement.
  • Keep length, area and angle units distinct.

Example 1

The rectangle has area 15 cm². Find .

Area = length × width. Divide both sides by the known width.

Example 2

The rectangle has area 20 cm². Find .

Area = length × width. Divide both sides by the known width.

Your turn

Question 1

The rectangle has area 25 cm². Find .

Check answer
Area = length × width. Divide both sides by the known width.
Question 2

The rectangle has area 30 cm². Find .

Check answer
Area = length × width. Divide both sides by the known width.
Question 3

The rectangle has area 35 cm². Find .

Check answer
Area = length × width. Divide both sides by the known width.
Question 4

The rectangle has area 40 cm². Find .

Check answer
Area = length × width. Divide both sides by the known width.
Question 5

The rectangle has area 45 cm². Find .

Check answer
Area = length × width. Divide both sides by the known width.
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