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Question P6 Seeing it move

Today’s problem — free all day, every step. Every day has one.

Kite paper — triangle LMN

Farhan has a square kite paper of side 28 cm. He cuts along the dotted lines to get one small square of area 16 cm² and 8 identical right-angled triangles. Triangle LMN is one such triangle. Find the length of LM.

The 28 cm square cut along the dotted lines into one small square and eight identical right-angled triangles, with triangle LMN drawn again beside it at the same scale. Drawn to scale.28 cm?LMN

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About this method

Seeing it move

Work out where the pieces land after a fold, cut or stack.

In this one. The same two triangle legs give both a sum and a difference: their sum is the outer side, while their difference is the small square’s side.

ABCDEFa straight strip of three: the two ends land opposite

How to spot it

Words like 'folded', 'cut along the dotted line' or 'stacked' appear beside a shape, and the question asks for a length or angle that only makes sense once the pieces are in their new positions.

Common mistake

Children try to calculate the answer before working out where the pieces actually end up, skipping the visualisation step that the whole question depends on.

Practise a similar question

Challenging Ravi has a square piece of canvas of side 31 cm. He cuts along the dotted lines to get one small square of area 289 cm² and 8 identical right-angled triangles. Triangle XYZ is one such triangle. Find the length of XY.
All 8 with this pattern →
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