For this case we have that by definition, the area of a rectangular space is given by:
[tex]A = w * l[/tex]
Where:
A: It's the area
w: It is the width
l: The length
If they tell us that[tex]l = 2w[/tex] and [tex]A = 18[/tex] we have:
[tex]18 = w * 2w\\18 = 2w ^ 2\\9 = w ^ 2\\w = \pm \sqrt {9}[/tex]
As we speak of a length, we take the positive root:
[tex]w = \sqrt {9}\\w = 3[/tex]
Answer:
The length is:
[tex]l = 2 * 3\\l = 6 \ meters[/tex]
