Using the cosine function:
[tex]\begin{gathered} \cos (\theta)=\frac{_{\text{ }}adjacent}{_{\text{ }}hypotenuse} \\ so\colon \\ \cos (45)=\frac{b}{16} \end{gathered}[/tex]
Solve for b:
[tex]\begin{gathered} b=16\cdot\cos (45) \\ b=8\sqrt[]{2} \end{gathered}[/tex]
