| Nominativ | triangulum, triangulum, triangulus, triangula, triangula, triangulus | trianguli, triangula, triangula, triangulae, triangulae, trianguli |
| Genitiv | triangulae, triangulae, trianguli, trianguli, trianguli, trianguli | triangulorum, triangulorum, triangulorum, triangularum, triangulorum, triangularum |
| Dativ | triangulo, triangulo, triangulo, triangulo, triangulae, triangulae | triangulis, triangulis |
| Akkusativ | triangulam, triangulam, triangulum, triangulum, triangulum, triangulum | triangula, triangula, triangulos, triangulas, triangulos, triangulas |
| Ablativ | triangula, triangula, triangulo, triangulo, triangulo, triangulo | triangulis, triangulis |
| Vokativ | triangula, triangule, triangulum, triangule, triangulum, triangula | trianguli, trianguli, triangula, triangula, triangulae, triangulae |
