Find the surface area of a textbook that is 2 in. × 14 in. × 9 in. (1 point) Responses 252 in.2 252 in. squared 50 in.2 50 in. squared 172 in.2 172 in. squared 344 in.2

1 answer

To find the surface area of a rectangular prism (which a textbook is), you 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, respectively. In this case, the dimensions are:

  • \( l = 2 , \text{in} \)
  • \( w = 14 , \text{in} \)
  • \( h = 9 , \text{in} \)

Now, let's calculate each term inside the parentheses:

  1. \( lw = 2 \times 14 = 28 , \text{in}^2 \)
  2. \( lh = 2 \times 9 = 18 , \text{in}^2 \)
  3. \( wh = 14 \times 9 = 126 , \text{in}^2 \)

Now, we sum these areas:

\[ lw + lh + wh = 28 + 18 + 126 = 172 , \text{in}^2 \]

Now, plug this sum into the surface area formula:

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

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

The correct response is 344 in.² (or 344 in²).