in order to find the cos of the angle formed, find the length of the triangle formed with the terminal ray.
[tex]\begin{gathered} r=\sqrt[]{(-4)^2+(3\sqrt[]{5})^2} \\ r=\sqrt[]{16+45} \\ r=\sqrt[]{61} \end{gathered}[/tex]
then, find the cos
[tex]\begin{gathered} \cos \theta=\frac{x}{r} \\ \cos \theta=-\frac{4}{\sqrt[]{61}} \\ \text{rationalize} \\ \cos \theta=-\frac{4\sqrt[]{61}}{61} \end{gathered}[/tex]
