What is the difference in the mean proportional between 1.8 and 3.2 and the third proportional to 5 and 3?
Show answer & explanation
Correct answer: D
Explanation
The correct answer is Option 4 i.e 0.6.
Let the mean proportional of 1.8 and 3.2 be x
x2 = 1.8 × 3.2 = 5.76
x = 2.4
Let the third proportional to 5 and 3 be a.
5 : 3 :: 3 : a
As one knows that the product of extremes is equal to the product of means.
5 × a = 3 × 3
a = 1.8
Required difference = 2.4 - 1.8 = 0.6