[tex] \sin\alpha=\dfrac{opposite}{hypotenuse}\\\\\cos\alpha=\dfrac{adjacent}{hypotenuse}\\\\\tan\alpha=\dfrac{opposite}{adjacent}\\\\\sec\alpha=\dfrac{1}{\cos\alpha}=\dfrac{hypotenuse}{adjacent}\\\\\text{We have:}\\opposite=3\\adjacent=4\\hypotenuse=5\\\\\text{subtitute:}\\\\\sin(A)=\dfrac{3}{5}\\\\\tan(A)=\dfrac{3}{4}\\\\\sec(A)=\dfrac{5}{4} [/tex]
