Answer:
[tex]cos(O)=\frac{9}{41}[/tex]
Step-by-step explanation:
Recall that [tex]cos(\theta)=\frac{adjacent}{hypotenuse}[/tex] in relation to the angle [tex]\theta[/tex].
We aren't given the hypotenuse, so we will use the two given side lengths to solve for the hypotenuse using the Pythagorean Theorem:
[tex]a^2+b^2=c^2[/tex]
[tex]9^2+40^2=c^2[/tex]
[tex]81+1600=c^2[/tex]
[tex]1681=c^2[/tex]
[tex]41=c[/tex]
Therefore, [tex]cos(O)=\frac{9}{41}[/tex]