To find the surface area of a rectangular prism (which is what a textbook is), you can use the formula:
\[ \text{Surface Area} = 2(lw + lh + wh) \]
where \( l \) is the length, \( w \) is the width, and \( h \) is the height.
Given dimensions:
- \( l = 14 \) in.
- \( w = 2 \) in.
- \( h = 9 \) in.
Now substitute the values into the formula:
\[ lw = 14 \times 2 = 28 \quad (\text{length × width}) \] \[ lh = 14 \times 9 = 126 \quad (\text{length × height}) \] \[ wh = 2 \times 9 = 18 \quad (\text{width × height}) \]
Now plug these values into the surface area formula:
\[ \text{Surface Area} = 2(28 + 126 + 18) \] \[ = 2(172) \] \[ = 344 \text{ in.}^2 \]
Thus, the surface area of the textbook is 344 in.².