Answer: 8.4 feet
Step-by-step explanation:
Given: Lumber required for each shelf = [tex]8\dfrac{3}{4}\ inches[/tex]
For each base side = [tex]12\dfrac12\ inches[/tex]
For each door stile = [tex]29\dfrac18\ inches[/tex]
Total lumber required = [tex](2\times 8\dfrac34 + 2\times12\dfrac12+2\times29\dfrac18)\ \ in.[/tex]
[tex]=(2\times\dfrac{35}{4}+2\times\dfrac{25}{2}+2\times\dfrac{233}{8})\ in\\\\= (\dfrac{35}{2}+25+\dfrac{233}{4})\ in.\\\\=\dfrac{403}{4}\ in. =\dfrac{403}{4}\times\dfrac1{12}\ feet \ \ \ \ [1 feet = 12 \ in.]\\\\\approx8.4\ feet[/tex]
Hence, we will need 8.4 feet lumber.