Posted by Joan on .
Hello! Can someone please help me out for this question?
The loudness, L, of a sound in decibels can be calculated using the formula L= 10 log(I/ F) where I is the intensity of the sound in watts per square metre and F= 10^ 12 . A singer is performing to a crowd. Determine the intensity of the singers voice if the sound level is 90 dB.
This is what i have so far:
90 = 10 log [ I/F]
10^1.9543 = 10 log [I/F]
What should i do now?
* F is really a (I) with a zero underneath..but i didn't know how to type that in

Grade 12 Advanced Functions Math 
Marth,
90 = 10 log [ I/F]
Use the properties of logarithms to isolate I.
9 = log(I/F)
10^9 = I/F