Chiàu kó͘-tiánkí-hô-ha̍k ê kóng-hoat, 1 êîⁿ (circle) iahkiû (sphere) ê1 tiâu poàⁿ-kèng (半徑) tō sī 1 ê toan-tiám tīîⁿ-sim iahkiû-sim, 1 ê toan-tiám tīîⁿ iahkiû téng-koân ê soàⁿ-koe̍h. Ah nāîⁿ iahkiû êpoàⁿ-kèng tō sī hit tiâu soàⁿ-koe̍h êtn̂g-tō͘. Poàⁿ-kèng sīti̍t-kèng chi̍t-poàⁿ tn̂g.
Tīkí-hô-ha̍k,kang-têng (engineering),tô͘-lūn (graph theory), ... khah khok-chhiong ê kóng-hoat, 1 hāng mi̍h-kiāⁿ, khó-pí kóngîⁿ-thiāu (cylinder),tô͘ (graph), iah sī ki-hâi ê lêng-kiāⁿ, téng-téng... êpoàⁿ-kèng tō sī i êtiong-sim (center) iahte̍k (axis) kaù i siōng goā-khaú ê tiám êkī-lî (distance).
