Which trig equation should be used to solve for the measure of angle C?

Explanation
We can find C using the cosine trigonometric function
[tex]\text{Cos C =}\frac{\text{Adjacent}}{Hypotenue}[/tex]Notice that adjacent =6 and hypotenuse =9. Therefore,
Answer:
[tex]\text{Cos C = }\frac{6}{9}[/tex]