Answer:
B) 12 feet.
Step-by-step explanation:
The area of a rectangle is given by:
[tex]A=w \ell[/tex]
Where w is the width and l is the length.
We are given that the length is twice the width. In other words:
[tex]\ell =2w[/tex]
We also know that the area is 72 square feet.
Substitute:
[tex]72=w(2w)[/tex]
Solve for w:
[tex]72=2w^2[/tex]
Divide both sides by two:
[tex]w^2=36[/tex]
And take principal square root of both sides:
[tex]w=\sqrt{36}=6[/tex]
So, the width is six feet.
And since the length is twice the width, the length is 12 feet.
Our answer is B.
