Explanation:
Step 1: List out all of the formulas for the trigonometric functions
sin(x) = opposite/hypotenuse
cos(x) = adjacent/hypotenuse
tan(x) = opposite/adjacent
Step 2: Find the value of RS
cos(31) = RS/24.8 NOT 24.8/RS
sin(31) = QS/24.8 NOT RS/24.8
sin(31) = QS/24.8 NOT 24.8/RS
cos(31) = RS/24.8 WHICH IS SAME AS RS/24.8
Answer: The correct length would be given from Option D, cos(31) = RS/24.8