Iruru muyu ( kastilla simipi : circunferencia ) huk pampa suyup hawan muyupayaq siq'im .

Kayhinam p'allta muyup iruru muyunpa minuywan :

${\displaystyle U=d\cdot \pi =2r\cdot \pi =2\pi r}$

${\displaystyle U}$: P'allta muyup iruru muyun

${\displaystyle r}$: P'allta muyup illwan

${\displaystyle \pi }$: Chiqaluwa (pi 3,14159265...)

${\displaystyle d}$: P'allta muyup raqtan