[tex]\begin{gathered} 1. \\ \text{when the length is 20, the area on the y-axi}s\text{ is 800 (Ans).} \\ 2. \\ For\text{ the area 600, there are two length,} \\ \text{one is }10\text{ and other 30.} \\ so,\text{ the smallest length is 10 (Ans).} \\ \text{and, the largesr side length is 30 (Ans).} \end{gathered}[/tex]
