[tex]width=\frac{2}{3}length\\\\
70=2width+2length\\\\
70=2length+2(\frac{2}{3}length)\\\\
70=2length+\frac{4}{3}length\\\\
70=\frac{10}{3}length\ \ | divide\ by\ \frac{10}{3}\\\\
70*\frac{3}{10}=length\\\\
length=21m\\\\
width=\frac{2}{3}*21=14m
[/tex]