Question

Find the surface area of a textbook that is
2 in. x 14 in. x 9 in. (1 point)
• 344 in.?
• 50 in.
2
• 252 in.?
• 172 in.?

Answer 1

To find the surface area of a rectangular prism (like a textbook), you can use the formula:

\[
\text{Surface Area} = 2(lw + lh + wh)
\]

where:
- \( l \) is the length,
- \( w \) is the width,
- \( h \) is the height.

In this case, the dimensions are:
- \( l = 14 \) in.
- \( w = 9 \) in.
- \( h = 2 \) in.

Now substituting these values into the formula:

\[
\text{Surface Area} = 2(14 \times 9 + 14 \times 2 + 9 \times 2)
\]

Calculating each term:

1. \( 14 \times 9 = 126 \)
2. \( 14 \times 2 = 28 \)
3. \( 9 \times 2 = 18 \)

Now sum these results:

\[
126 + 28 + 18 = 172
\]

Now multiply by 2:

\[
\text{Surface Area} = 2 \times 172 = 344 \text{ in.}^2
\]

So the surface area of the textbook is **344 in.²**.