Recall
[tex]1\text{ foot = 12inches}[/tex]
Given parameters
Length =12inches
Breadth = 8inches
Height =6 inches
Step 1
Formula
The total surface area of a cuboid
[tex]\text{The total surface area }of\text{ a cuboid =2(lb+bh+hl)}[/tex]
Step 2
Substitute the given parameters
[tex]\begin{gathered} \text{The total surface area }of\text{ a cuboid =2((}12\times8)\text{+(8}\times6)\text{+(6}\times12)\text{)} \\ \text{The total surface area }of\text{ a cuboid =2((96})\text{+(48})\text{+(72})\text{)} \\ \text{The total surface area }of\text{ a cuboid =2(216)} \\ \text{The total surface area }of\text{ a cuboid =}432in^2 \end{gathered}[/tex]
The final answer
The amount of wrapping paper that Joanna needs is 432 square inches
