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

1 answer

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 \( \boxed{344 , \text{in}^2} \).