[tex]\bf \textit{sum of a finite arithmetic sequence}
\\\\
S_n=\cfrac{n(a_1+a_n)}{2}\qquad
\begin{cases}
n=n^{th}\ term\\
a_1=\textit{first term's value}\\
----------\\
n=54\\
a_1=6\\
a_{54}=377
\end{cases}
\\\\\\
S_{54}=\cfrac{54(6+377)}{2}\implies S_{54}=\cfrac{54(383)}{2}
\\\\\\
S_{54}=\cfrac{2062}{2}\implies S_{54}=10341[/tex]
