[tex]\begin{gathered} \text{ Given an acute angle }\theta\text{ in a right-angled triangle, then} \\ \end{gathered}[/tex][tex]\cos \theta=\frac{\text{ length of the side adjacent to angle }\theta}{\text{ length of the hypotenuse}}[/tex]
The side adjacent to The length of BC = 45
The length of AC = 51
Therefore,
[tex]\cos C=\frac{45}{51}=\frac{15}{17}[/tex]
