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This problem is all about visualisation and symmetry; it might take a while to get to grips with the visualisation, and coordinates could be useful.
What happens when you rotate the cube about an axis through opposite vertices?
A and B are two points on a circle centre O. Tangents at A and B cut at C. CO cuts the circle at D. What is the relationship between areas of ADBO, ABO and ACBO?
Ten squares form regular rings either with adjacent or opposite vertices touching. Calculate the inner and outer radii of the rings that surround the squares.