| Singular | Plural | |
|---|---|---|
| Nominativ | trigonium, trigonium | trigonia, trigonia |
| Genitiv | trigoni, trigoni, trigonii, trigonii | trigonium, trigonium, trigoniorum, trigoniorum |
| Dativ | trigonio, trigonio | trigoniis, trigoniis |
| Akkusativ | trigonium, trigonium | trigonia, trigonia |
| Ablativ | trigonio, trigonio | trigoniis, trigoniis |
| Vokativ | trigonium, trigonium | trigonia, trigonia |