Question

Find the surface area of a textbook that is 2 in. × 14 in. × 9 in.
(1 point)
Responses

344 in.2

252 in.2

172 in.2

50 in.2

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, and \( h \) is the height.

Given the dimensions of the textbook:
- \( l = 14 \) in.
- \( w = 2 \) in.
- \( h = 9 \) in.

Let's calculate each of the areas:

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

Now, combine these:

\[
lw + lh + wh = 28 + 126 + 18 = 172
\]

Now, multiply by 2 to get the surface area:

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

So, the surface area of the textbook is \( \boxed{344 \, \text{in}^2} \).