A power ratio of 9000000:1 corresponds to ... dB?

69.54

Explanation:

A power ratio of 9000000:1 corresponds to 69.54 dB.

The calculation is presented below:

Formula for calculating Power ratio (db) = 10 * log [P (out) / P (in) ]

Since the given ratio is 9000000:1, substituting in the formula gives us 10 * log (9000000/1)

Note that log 9000000 = 6.954

Therefore, 10 * log (9000000/1) = 69.54

Hence the required power ratio in db is 69.54 db.