Antes de calcular o seno, o cosseno e a tangente devemos encontrar quanto vale a hipotenusa,...
[tex](\text{hip})^2=(\text{cat op})^2+(\text{cat adj})^2\\\\(\text{hip})^2=12^2+5^2\\\\(\text{hip})^2=169\\\\(\text{hip})=13[/tex]
Segue,
[tex]\star \sin a=\frac{\text{cat op}}{\text{hip}}\Rightarrow\boxed{\sin a=\frac{12}{13}}\\\\\star \cos a=\frac{\text{cat adj}}{\text{hip}}\Rightarrow\boxed{\cos a=\frac{5}{13}}\\\\\star \tan a=\frac{\text{cat op}}{\text{cat adj}}\Rightarrow\boxed{\tan a=\frac{12}{5}}[/tex]
