Answer:
C. cos(31°) = RS/24.8
Explanation:
The mnemonic SOH CAH TOA reminds you of the relation between the adjacent side and the hypotenuse and the trig function of an angle:
Cos = Adjacent/Hypotenuse
In the given triangle, the side adjacent to the 31° angle is RS. The hypotenuse is marked as 24.8. So, the relationship you seek is ...
cos(31°) = RS/24.8 . . . . . matches choice C