Final answer:
The question lacks sufficient context to accurately express cos S as a fraction. Further information or clarification is needed regarding the meaning of S, R, and the values 25 and 24.
Step-by-step explanation:
The question "Express cos S as a fraction in simplest terms.a) 25b) Rc) 24" seems to contain some ambiguity, and appears to involve a trigonometric function. However, without further context or a diagram indicating what S, R, and the values 25 and 24 refer to, it's impossible to provide an accurate answer.
Trigonometric functions, such as cosine, typically involve ratios of sides of a right triangle or unit circle values. In order to express cos S as a fraction, one would typically refer to the known values or measurements from a geometric figure. It could be a ratio like adjacent side over hypotenuse in the context of a right triangle, but this cannot be ascertained without more information.
If the student can provide additional information or clarify the context for the values given (a) 25 (b) R (c) 24, and the variable S, a specific and accurate answer can be offered.