Find the surface area of a textbook that is 2 in. × 14 in. × 9 in.

(1 point)
Responses

252 in.2
252 in. squared

172 in.2
172 in. squared

50 in.2
50 in. squared

344 in.2

1 answer

To find the surface area of a rectangular prism (which a textbook can be approximated as), we can use the formula:

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

where \( l \), \( w \), and \( h \) are the length, width, and height of the prism.

For the textbook with dimensions of \( 2 , \text{in} \) (width), \( 14 , \text{in} \) (length), and \( 9 , \text{in} \) (height), we have:

  • \( l = 14 \) in
  • \( w = 2 \) in
  • \( h = 9 \) in

Now, we can calculate each term in the formula:

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

Now, add these areas together:

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

Now multiply by 2 to get the total surface area:

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

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

The correct response is: 344 in.² (or 344 in. squared)