The area of a rectangle is given by the product of its dimensions.
If the rectangle area is 200 ft² and the dimensions are 2x and x, we have:
[tex]\begin{gathered} 200=2x\cdot x \\ 2x^2=200 \\ x^2=100 \\ x=10 \end{gathered}[/tex]
The total fencing needed is (2x+2x+x+x) from the perimeter and (x+x) from the internal fencing, so:
[tex]\begin{gathered} (2x+2x+x+x)+(x+x) \\ =6x+2x \\ =8x \\ =8\cdot10 \\ =80\text{ ft} \end{gathered}[/tex]
Therefore the correct option is d.
