Feuerbach's Theorem/Historical Note

Historical Note on Feuerbach's Theorem

Feuerbach's Theorem was proved in $1822$ by Karl Wilhelm Feuerbach.

This was two years after Jean-Victor Poncelet and Charles Julien Brianchon had demonstrated the existence of the nine point circle, now known as the Feuerbach circle.

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $9$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $9$