In a right triangle, the side adjacent to angle θ is 12 and the hypotenuse is 13. Find cos(θ).

For a right triangle, cosine compares the length of the side adjacent to the angle to the length of the hypotenuse.

Use the cosine ratio:
cos(θ) = adjacent / hypotenuse

The adjacent side is 12 and the hypotenuse is 13, so:
cos(θ) = 12 / 13

The fraction cannot be simplified further.

Therefore, cos(θ) = 12/13.