Exercises: Sine and Cosine of Complementary Angles

In a right triangle with legs of length 3 and 4 and hypotenuse of length 5, if $\theta$ is the angle opposite the side of length 3, then $\sin(\theta) = \dfrac{\text{opposite}}{\text{hypotenuse}} = \dfrac{\hspace{0.2em}\fbox{\phantom{000000}}\hspace{0.2em}}{\hspace{0.2em}\fbox{\phantom{000000}}\hspace{0.2em}}$ and $\cos(\theta) = \dfrac{\text{adjacent}}{\text{hypotenuse}} = \dfrac{\hspace{0.2em}\fbox{\phantom{000000}}\hspace{0.2em}}{\hspace{0.2em}\fbox{\phantom{000000}}\hspace{0.2em}}$.