Question

78 is the geometric mean of 30 and what number

Answer 1

202.8

Explanation:

The geometric mean of 2 numbers a and b is

`√(ab)`

Here a = 30 and mean = 78, thus

`√(30b)` = 78

To clear the radical square both sides

(
`√(30b)` )² = 78², that is

30b = 6084 ( divide both sides by 30 )

b =
`(6084)/(30)` = 202.8