An open box is formed by cutting squares with side lengths of 4 inches from each corner of a square piece of paper. What is a side length of the original paper if the box has a volume of 784 cubic inches?
Since 4 inches were cut from each corner of the square piece of paper, we have
Since the original paper is square and the length cut from each side is the same, the resulting base is still square.
Now, what we want is the length of the original paper.
Since we folded the paper from each side, we need to add the length of opposite sides (i.e. 2 instances) of the folded part to get
the original length