The dimensions of the original piece of cardboard are 15 inches by 23 inches.
Let's start by defining the variables we'll need for this problem:
w = width of the original piece of cardboard (in inches)
l = length of the original piece of cardboard (in inches)
h = height of the box (in inches)
We know that the length of the original piece of cardboard is 8 inches more than the width, so we can write:
l = w + 8
When Lorene cuts out 4-inch squares from each corner of the rectangular sheet, the resulting height of the box will be 4 inches. Therefore, the height of the box is:
h = 4
The base of the box will have dimensions (w - 8) inches by (l - 8) inches, since 4 inches are removed from each side of the width and length. The volume of the box is given as 420 cubic inches, so we can write:
V = (w - 8)(l - 8)(4)
Substituting the expression for l in terms of w, we get:
420 = (w - 8)(w + 8 - 8)(4)
420 = (w - 8)(w)(4)
105 = w(w - 8)
Solving for w using the quadratic formula, we get:
w = 15 or w = -7
Since w must be a positive value, we can discard the solution w = -7. Therefore, the width of the original piece of cardboard is:
w = 15 inches
Using the expression for l in terms of w, we can find the length of the original piece of cardboard:
l = w + 8 = 23 inches
Therefore, the dimensions of the original piece of cardboard are 15 inches by 23 inches.