Wow! Excellent proof. I would never have thought of that. Have a gold medal:
Bob
]]>Yes, I got that value to, just by calculation in Excel. But I guess you want an analysis of how to get this by algebra etc. I've been working on this, on and off, for two days and haven't got a method yet. My first attempt was to try and simplify the trig. using various trig. identities. Just went round in circles with that. Then I made a diagram with a 14 point polygon inscribed in a circle, and tried to find a method using the distances in right angled triangles plus similar triangles, angles in semi circle etc. I think that is the way to go with this, but a solution still alludes me. If I still cannot get anywhere by the end of today, I'll post my diagram. Maybe someone else can spot what I'm missing.
Bob
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