Can anyone help me figure out what this is

Explanation:

Cosine of an angle is the ratio of the adjacent over the hypotenuse.

For reference angle A, the adjacent leg or closest leg is side AB = 30.

The hypotenuse is always the longest side. The longest side of a right triangle is always opposite the largest angle (the 90 degree angle). So the hypotenuse is AC = 34.

We then say:

cos(angle) = adjacent/hypotenuse

cos(A) = AB/AC

cos(A) = 30/34

cos(A) = (2*15)/(2*17)

cos(A) = 15/17

where are the choices?