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## 'A Square in a Circle' printed from http://nrich.maths.org/

Harry had a circle which was marked with twelve numbered dots to
help him draw clock faces. The circle had a diameter of $10$
cm.

Harry drew lines from the $12$ to the $3$, from the $3$ to the
$6$, from the $6$ to the $9$, and then back from the $9$ to the
$12$.

What shape had he drawn?

Find the area of the shape.

Harry had lots of centimetre square tiles.

He covered as much of his shape as he could with whole tiles
without going over the edge.

What was the largest number of whole tiles he could fit in?