Ptolemy's theorem from proj.math documentary
![](https://i.ytimg.com/vi/ZK08Z5A9xH4/mqdefault.jpg)
4:12
A Beautiful Proof of Ptolemy's Theorem.
![](https://i.ytimg.com/vi/o3QBgkQi_HA/mqdefault.jpg)
6:56
Pentagons and the Golden Ratio - Numberphile
![](https://i.ytimg.com/vi/1EkoaQJyrfk/mqdefault.jpg)
6:28
How To Solve For The Radius. Challenging 1970s Math Contest!
![](https://i.ytimg.com/vi/TlzCEwGp4VM/mqdefault.jpg)
7:02
How to Prove Ptolemy's Theorem for Cyclic Quadrilaterals
![](https://i.ytimg.com/vi/bJOuzqu3MUQ/mqdefault.jpg)
38:28
A Miraculous Proof (Ptolemy's Theorem) - Numberphile
![](https://i.ytimg.com/vi/rr1fzjvqztY/mqdefault.jpg)
32:54
Ptolemy’s Theorem and the Almagest: we just found the best visual proof in 2000 years
![](https://i.ytimg.com/vi/eX2WZennPhU/mqdefault.jpg)
5:11
A Fun Proof of Van Aubel's Theorem.
![](https://i.ytimg.com/vi/c3RBovxYvC0/mqdefault.jpg)
7:43