The perimeter of a parallelogram is twice the sum of the length and the width.
The length is x.
The width is 4 meters less than its length, so it's x-4.
The perimeter is 72 meters.
[tex]2(x+x-4)=72 \\
2(2x-4)=72 \ \ \ \ \ \ \ |\div 2 \\
2x-4=36 \ \ \ \ \ \ \ \ \ \ \ |+4 \\
2x=40 \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ |\div 2 \\
x=20 \Leftarrow \hbox{the length} \\ \\ \hbox{the width:} \\
x-4=20-4=16[/tex]
The length is 20 meters, the width is 16 meters.
