Question

Two numbers, 3 and a, have a geometric mean of 9. Find the value of a.

Answer 1

The geometric mean of two numbers x and y is √(xy).

So, if the geometric mean of 3 and a is 9 =>

9 = √(3a)

=> 9^2 = 3a

=> a = 9^2 / 3

a = 81 / 3

a = 27

Answer: the value of a is 27.