Problem 9 · 2011 Math Kangaroo
Medium
Spatial & Visual Reasoning
tiling-tessellationcomposition
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Answer: E — Shape E.
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Hint 1 of 2
The four card pieces have curved bumps and dents that must pair up with no gaps.
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Hint 2 of 2
Check each outline: the bumps and dents must exactly cancel to fill it.
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Approach: fit the four pieces into each outline
- The four pieces have matching rounded bumps and notches that should slot together with no overlap.
- Four of the outlines can be filled by arranging the pieces so every bump meets a matching dent.
- Outline E cannot be made: its boundary leaves a mismatch the pieces cannot fill.
- So the impossible shape is E.
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