The trigonometric ratios are defined as
[tex]\begin{gathered} \sin \theta=\frac{opposite}{hypothenuse} \\ \cos \theta=\frac{adjacent}{hypothenuse} \\ \tan \theta=\frac{opposite}{adjacent} \end{gathered}[/tex]
For the given triangle, the adjacent side to ∠Z is ZT=40 and the hypothenuse is ZX=41
So the cosine of ∠Z can be determined as
[tex]\cos (Z)=\frac{40}{41}[/tex]
