The ratio of the third proportional to 16 & 40 and the mean proportional between 10 & 40 is:A5 ∶ 1B1 ∶ 5C4 ∶ 1D1 ∶ 4Answer: A. 5 ∶ 1 Read Explanation: mean proportion of 10 & 40 = √400 = 20 Third proportion of 16 & 40 = (40)²/16 = 100 Required ratio = 100 : 20 = 5 : 1Read more in App