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Sunday Afternoon Maths LXVICryptic crossnumber #2
Sunday Afternoon Maths LXVCryptic crossnumber #1
Square and cube endings
Sunday Afternoon Maths LXIVEqual lengths
Sunday Afternoon Maths LXIIIIs it equilateral?
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There is a quarter circle with radius 2r and centre A and two semi circles with radius r and centres B and C.
Prove that the red area is equal to the blue area.