Structuring a beamer frame

i have a problem in a Beamer frame.

As you see in the left bottom corner there is a formula that isn't fitting very well, I would like to know if there is a way of fixing this without changing the letter size.

Here is the code for that frame:

\begin{frame}{Desarrollo $\zeta$}
\begin{itemize}
\item Se calculan las constantes \pause
\end{itemize}
$$Overshoot\, (\%) = e^{-\frac{\zeta\pi}{\sqrt{1-\zeta^2}}} * 100\% \pause$$
\begin{equation*}
Overshoot = 20\% \pause
\end{equation*}

Ahora se despeja para $\zeta$
\begin{equation*}
20\% = e^{-\frac{\zeta\pi}{\sqrt{1-\zeta^2}}} * 100\% \pause
\end{equation*}
\begin{equation*}
\zeta = \frac{\textnormal{ln(5)}}{\sqrt{\pi^2+\textnormal{[ln(5)]}^2}}
\end{equation*}

Más generalmente: \pause

\begin{equation*}
\zeta = \frac{\textnormal{ln(X)}}{\sqrt{\pi^2+\textnormal{[ln(X)]}^2}
\\
\small{X = {[MP]}^-1}
}
\end{equation*}
\end{frame}


Thank you very much!

Here's a solution that's quite similar to the one in @Zarko's answer. The main differences are (a) the use of inline-style fractions instead of \frac notation, (b) the use of \exp(...) notation instead of e^{...}, and (c) the use of a single align environment along with two \intertext statements.

\documentclass{beamer}
\usepackage{mathtools}
\begin{document}
\begin{frame}{Desarrollo $\zeta$}
\begin{itemize}
\item Se calculan las constantes
\begin{align}
Overshoot\, (\%) &= \exp(-\zeta\pi\big/\sqrt{1-\zeta^2}\,) \cdot 100\%   \\
Overshoot &= 20\%\notag
\intertext{Ahora se despeja para $\zeta$:}
20\% &= \exp(-\zeta\pi\big/\sqrt{1-\zeta^2}\,) \cdot 100\% \notag  \\
\zeta &= \ln 5\big/\sqrt{\pi^2+[\ln 5]^2} \notag \\
\intertext{Más generalmente:}
\zeta &= \ln(X)\big/\sqrt{\pi^2+[\ln X]^2} \notag\\
X &= [MP]^{-1} \notag
\end{align}
\end{itemize}
\end{frame}
\end{document}

• +1 for giving credit to an earlier answer which has overlap with yours, – Schrödinger's cat Dec 18 '19 at 5:40
• @Schrödinger'scat - Many thanks! I guess it still shows that I was once an academic researcher: I simply cannot help but give credit to prior work in any field I'm working on... Plus, Zarko's answer is very goodi in its own rights! – Mico Dec 18 '19 at 15:33
• you not provide your document preamble, so the frame layout with suggested MWE is different from yours
• for equations are used align environment defined in amsmath package
• LaTeX has defined operator ln
• for units is sensible to use siunitx package
\documentclass{beamer}
\usepackage{amsmath}
\usepackage{siunitx}

\begin{document}
\begin{frame}[fragile]
\frametitle{Desarrollo $\zeta$}
\begin{itemize}
\item Se calculan las constantes \pause
\begin{align}
\text{Overshoot (\%)}
& = \mathrm{e}^{-\frac{\zeta\pi}{\sqrt{1-\zeta^2}}\ast\SI{100}{\%}}          \\   \pause
& = \SI{20}{\%}   \notag \pause
\end{align}
Ahora se despeja para $\zeta$
\begin{align*}
\SI{20}{\%} & = \mathrm{e}^{-\frac{\zeta\pi}{\sqrt{1-\zeta^2}}}\ast\SI{100}{\%}  \\   \pause
\zeta   & = \frac{\ln(5)}{\sqrt{\pi^2+ [\ln(5)]^2}}
\end{align*}
Más generalmente: \pause
\begin{align*}
\zeta & = \frac{\ln(X)}{\sqrt{\pi^2+ [\ln(X)]^2}}\\
X & = [MP]^{-1}
\end{align*}
\end{itemize}
\end{frame}
\end{document}