# Tony Foster's Proof of Viviani's Theorem

### What Might This Be About?

23 February, 2017, Created with GeoGebra

### Viviani's Theorem

The sum of distances of a point inside an equilateral triangle or on one of its sides equals the length of its altitude.

The theorem is named after Vincenzo Viviani (1622-1703).

### Proof

### Acknowledgment

The above is a slight modification of Tony Foster's proof of Viviani's theorem.

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