# Barbier's theorem

> theorem that every curve of constant width has perimeter π times its width

**Wikidata**: [Q1188048](https://www.wikidata.org/wiki/Q1188048)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Barbier's_theorem)  
**Source**: https://4ort.xyz/entity/barbier-s-theorem


## References

1. Freebase Data Dumps. 2013