[tex]\bf n^{th}\textit{ term of a geometric sequence}\\\\
a_n=a_1\cdot r^{n-1}\qquad
\begin{cases}
n=n^{th}\ term\\
a_1=\textit{first term's value}\\
r=\textit{common ratio}\\
----------\\
a_1=5\\
r=3\\
n=5
\end{cases}
\\\\\\
a_n=5\cdot 3^{n-1}\implies a_5=5\cdot 3^{5-1}
\\\\\\
a_5=5\cdot 3^4\implies a_5=5\cdot 81\implies a_5=405[/tex]
