P=2·(L+l)=38,5 => L+l=38,5:2 => L+l=19,25
l=[tex] \frac{2}{9} [/tex]·L
L+l=19,25=> L+[tex] \frac{2}{9} [/tex]·L=19,25 => 9L+2L=173,25=> 11L=173,25 => L=15,75cm
l=[tex] \frac{2}{9}[/tex]·L=[tex] \frac{2}{9} [/tex]·15,75=3,5cm
A=L·l=15,75·3,5=55,125cm²