A difficult geometry puzzle with an elegant solution.
Practice more problem-solving at https://brilliant.org/3b1b
Solution to the puzzle mentioned at the end: https://brilliant.org/3b1bindicator/
Special thanks to the following patrons:
http://3b1b.co/putnam-thanks
These videos exist thanks to Patreon:
https://www.patreon.com/3blue1brown
A different write-up of this solution:
http://lsusmath.rickmabry.org/psisson/putnam/putnam-web.htm
1992 Putnam with this problem:
http://kskedlaya.org/putnam-archive/
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