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Squaring the Circle

Bluey-green, white and transparent squares with a few odd bits of shapes around the perimeter. But, how many squares are there of each type in the complete circle? Study the picture and make an estimate.

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Where Am I?

From the information you are asked to work out where the picture was taken. Is there too much information? How accurate can your answer be?

Interstellar

Age 11 to 14 Short Challenge Level:

Answer: $19$


   $\tfrac x5$ is between $3$ and $4$
$\therefore x$ is between $15$ and $20$
So $x=19$


This problem is taken from the UKMT Mathematical Challenges.
You can find more short problems, arranged by curriculum topic, in our short problems collection.