Kiú-piên-hìn
外觀
![](http://chped.net/https/upload.wikimedia.org/wikipedia/commons/thumb/b/ba/Regular_polygon_9_annotated.svg/390px-Regular_polygon_9_annotated.svg.png)
Kiú-piên-hìn (Yîn-ngî: Nonagon) he kiú-piên ke Tô-piên-hìn, Chang Kiú-piên-hìn he kiú-kok siông-tén. Nui-kok vì 140°. Ngiâ piên-chhòng vì , mien-chit . Ngiâ-yû chang kiú piên hìn , . Kì he ki Chang chhit-piên-hìn heu nang yit-ke put-nèn chhak-kûi chok-thù ke chang Tô-piên-hìn.
Chang Kiú-piên-hìn chhak-kûi chok-thù[phiên-siá | kói ngièn-sṳ́-mâ]
![Chang Kiú-piên-hìn.](http://chped.net/https/upload.wikimedia.org/wikipedia/commons/thumb/d/d2/Approximated_Nonagon_Inscribed_in_a_Circle.gif/450px-Approximated_Nonagon_Inscribed_in_a_Circle.gif)