Let the lengths of the sides be x and y respectively. Then;
[tex] \frac{x}{y} = \frac{2}{3} [/tex]
x=[tex] \frac{2}{3} y[/tex]
We also know that x+y=50
Replacing value of x;
[tex] \frac{2}{3} y+y=50
[/tex][tex]2y+3y=150[/tex]
5y=150
y=30
x=[tex] \frac{2}{3} *30[/tex]
x=20
The length of the sides of parallelogram are 20cm and 30 cm.