Answer:
[tex]cos(C)=\frac{\sqrt{1,353}}{{41}}[/tex]
Step-by-step explanation:
step 1
In the right triangle CDE find the length side of the hypotenuse, aoolying the Pythagoras Theorem
[tex]DC^{2}=4^{2}+(\sqrt{66})^{2}\\ \\DC^{2}=82\\ \\DC=\sqrt{82}\ units[/tex]
step 2
Find the cos(C)
[tex]cos(C)=\frac{\sqrt{66}}{\sqrt{82}}=\frac{\sqrt{33}}{\sqrt{41}}=\frac{\sqrt{1,353}}{{41}}[/tex]
