The total surface area of a rectangular prism can be calculated using the formula shown below:
Where "l" is the length, "w" is the width and "h" is the height of the rectangular prism.
In this case you know that:
As you can notice, you need to make the conversion of the length from feet to inches. Remember that:
Therefore:
Then, the length in inches is:
Now you can substitute values into the formula and then evaluate, in order to find the total surface area of the rectangular prism:
The answer is: