[tex]\bf \textit{area of a triangle}\\\\
A=\cfrac{1}{2}bh~~
\begin{cases}
A=\frac{2}{5}\\\\
h=\frac{6}{5}
\end{cases}\implies \cfrac{2}{5}=\cfrac{1}{2}\left( b\cdot \cfrac{6}{5} \right)\implies \cfrac{2}{5}=\cfrac{6b}{10}
\\\\\\
\cfrac{20}{5}=6b\implies \cfrac{20}{30}=b\implies \cfrac{2}{3}=b[/tex]
