Different way for logarithms?

[professionalbronco]

So we need to solve the equation $\pi^x=10^9.$ In order to solve for $x$, we just need one simple step: take $\log_{\pi}$ of both sides. This means that

$$\log_{\pi}\pi^x=\log_{\pi}10^9\implies x=\log_{\pi}10^9\approx 18.1.$$

This however, cannot be done with a calculator. (A calculator only has log and log base $e$.)