[tex] \bf \textit{area of a rectangle}\\\\
A=Lw~~
\begin{cases}
L=length\\
w=width\\
--------\\
A=7.7682\times 10^4\\
w=2.42\times 10^2
\end{cases}\implies 7.7682\times 10^4=L(2.42\times 10^2)
\\\\\\
\cfrac{7.7682\times 10^4}{2.42\times 10^2}=L\implies \cfrac{77682}{242}=L\implies 321=L\implies 3.21\times 10^2=L [/tex]
