Pentagons and the Golden Ratio – Numberphile

Continuing on from Zvezda’s previous video about Ptolemey’s Theorem (see: https://youtu.be/bJOuzqu3MUQ) now we use it to prove some cool stuff with pentagons and equilateral triangles.
More links & stuff in full description below ↓↓↓

Zvezda’s Numberphile playlist: http://bit.ly/zvezda_videos

Zvezda’s webpage: https://math.berkeley.edu/~stankova/

Golden Ratio: https://youtu.be/sj8Sg8qnjOg

Epic Circles: https://youtu.be/sG_6nlMZ8f4

Triangle Magic Highway: https://youtu.be/wVH4MS6v23U

Numberphile is supported by the Mathematical Sciences Research Institute (MSRI): http://bit.ly/MSRINumberphile

We are also supported by Science Sandbox, a Simons Foundation initiative dedicated to engaging everyone with the process of science. https://www.simonsfoundation.org/outreach/science-sandbox/

And support from Math For America – https://www.mathforamerica.org/

NUMBERPHILE
Website: http://www.numberphile.com/
Numberphile on Facebook: http://www.facebook.com/numberphile
Numberphile tweets: https://twitter.com/numberphile
Subscribe: http://bit.ly/Numberphile_Sub

Videos by Brady Haran

Patreon: http://www.patreon.com/numberphile

Numberphile T-Shirts and Merch: https://teespring.com/stores/numberphile

Brady’s videos subreddit: http://www.reddit.com/r/BradyHaran/

Brady’s latest videos across all channels: http://www.bradyharanblog.com/