Answer: length is 30
Step-by-step explanation:
length times width is area
A= L * W
W= 2/3L
600= L * [tex]\frac{2}{3}[/tex]L
[tex]600=\frac{2}{3} L^{2} \\\frac{3}{2} (600)=L^{2} \\900=L^{2} \\30=L[/tex]