Answer
(3 ft) $\times$ (6 ft).
Work Step by Step
Let the sheet metal have width x and length 2x.
Taking away two 1-foot lengths from the width,
and two 1-foot lengths from the height of the sheet, what remains is a base rectangle
with area $(x-2)(2x-2) $.
The height of the box is 1,
so we are given (with volume =4)
$(x-2)(2x-2)=4$
$2x^{2}-2x-4x+4=4$
$2x^{2}-6x+4-4=0$
$2x^{2}-6x=0$
$2x(x-3)=0$
The x=0 solution makes no sense,
so the only solution is x=$3$.
The width is 3 ft, so the length is $2x=6$ ft.
The original sheet is (3 ft) $\times$ (6 ft).
