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Reflecting Squarely

Age 11 to 14
Challenge Level Yellow star
Secondary curriculum
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An excellent solution from Andrei of School 205 Bucharest. I like this very much because of the effective and systematic approach he took to investigating the problem.

Here is Andrei's solution:

I worked systematically. I took the big (yellow) piece and I placed the rectangle in all the possible locations around it (both vertically and horizontally). Then I looked if the figure admitted a symmetry line (vertical, horizontal, or at a 45$^{\circ}$ angle) if I added a small square (blue). Here is all my work and the solutions I found, with the corresponding symmetry line:


Sara spotted that Andrei had missed a solution. Here is Sara's complete set - her last solution is the one missing in the list above.

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The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice.

NRICH is part of the family of activities in the Millennium Mathematics Project.

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