The length of the diagonal of a box is given by

$$D=\sqrt{L^{2}+W^{2}+H^{2}}$$

where $L, W,$ and $H$ are, respectively, the length, width, and height of the box. Find the length of the diagonal $D$ of a box that is 4 ft long, 2 ft wide, and 3 ft high. Give the exact value, and then round to the nearest tenth of a foot.

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