How do I find the approximate value of #log_5 100#?
Well, for starters, remember that logs are really just powers in reverse!
If you know some powers of 5, then just keep going...
Use a scientific calculator (at least) to continue guessing:
However, some calculators will give you a much better answer, and much faster:
If you don't have this kind of option on your calculator, try some online: Online log calc