Today’s problem — free all day, every step. Every day has one.
Devi's square — eight triangles
Devi has a square of paper of side 23 cm. She cut along the dotted lines to get one small square of area 49 cm² and 8 identical right-angled triangles. Triangle PQR is one such triangle. Find the length of PQ.
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65 worked examples are free without a code, two from every pattern. No account, either way.
The pattern behind it: Seeing it move
Work out where the pieces land after a fold, cut or stack.
In this one. The two legs of one triangle lie end to end along a side of the big square, so they add to 23, while the small square's side is their difference, 7 — sum and difference give both legs at once.
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.
Try one like it
Challenging Canvas — cut into a square and eight triangles 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 iden…The 33 problem patterns
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
A PDF, and a note when new solutions go up.