Shape and Space 7

2 marks · Normal

The areas of two similar rectangles are 45 cm² and 125 cm². If the shorter side of the smaller rectangle is 5 cm, calculate the corresponding side of the larger rectangle.

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8.33 cm (±0.01)

Also accept: 8.33 cm; 8.3 cm

Common mistakes: Multiplying by the square root instead of dividing

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Marking points

M1 · 1 mark · Finds linear scale factor √(125/45).

A1 · 1 mark · Correct calculation: 5 × √(125/45) = 8.33 cm (2 d.p.).

Worked solution

Scale factor = √(125/45) = √(2.777...) = 1.666...

Corresponding side = 5 × 1.666... = 8.33 cm