SAT Math Multiple Choice Practice Question 47: Answer and Explanation
3. If the ratio of k to m is the same as the ratio of m to n, then which of the following must be true?
A. kn = m2
B. k + m = m + n
C. kn = 2m
D. km = mn
E. k - m = m - n
Correct Answer: A
A. Ratio is just a fancy name for fraction, so this problem says that k/m = m/n. Cross-multiplying gives you kn = m2, or Choice (A).