How do I find the base when Log is given I'm trying to figure out how to calculate the base if:

$$ \log_b 30 = 0.30290 $$

How do I find $b$ ?

I've slaved over the Wikipedia page for logarithms, but I just don't get the mathematical notations.

If someone could let me know the steps to find $b$ in plain english, I'd be eternally grateful!
You need to think about the definitions. 

Since $a^b=c$ can be rewritten as $\log_a c = b$. 

That should tell you that, 

$$b^{0.30290} = 30$$ 

and then, 

$$b = \exp {\frac{\ln 30}{0.30290}} $$
In Excel: to quickly calculate the elusive "e":

To calculate "e" (the base of LN):
e = x^(1/LN(x))
Wherein: x = any number >or&lt; 1 but > 0