We know that the length of a rectangle is twice its width. Then:
The area of a rectangle is the product of its width and length. Then:
[tex]A=2x\cdot x=2x^2[/tex]
Additionally, we know that the area is 162 in². Using the expression above we can obtain the value of x:
[tex]\begin{gathered} 162=2x^2 \\ 81=x^2 \\ x=9\text{ in} \end{gathered}[/tex]
Finally, the perimeter (2P) is just twice the sum of the width and the length of the rectangle:
[tex]2P=2\cdot(2x+x)=6x=6\cdot9=54\text{ in}[/tex]
