Filip is making a crate that is a prism with a square base. The base side length is 8 in. and the height of the prism is 20 in. Which of the following correctly calculates the surface area of this prism?

1 answer

To calculate the surface area of a prism with a square base, you can use the formula:

\[ \text{Surface Area} = 2B + Ph \]

where:

  • \(B\) is the area of the base,
  • \(P\) is the perimeter of the base, and
  • \(h\) is the height of the prism.
  1. Calculate the base area (B):

    • The base is square, so the area \(B\) is given by: \[ B = \text{side}^2 = 8 , \text{in} \times 8 , \text{in} = 64 , \text{in}^2 \]
  2. Calculate the perimeter (P):

    • The perimeter of a square is given by: \[ P = 4 \times \text{side} = 4 \times 8 , \text{in} = 32 , \text{in} \]
  3. Use the height (h):

    • Given height \(h = 20 , \text{in}\).
  4. Plug these values into the surface area formula: \[ \text{Surface Area} = 2B + Ph = 2(64 , \text{in}^2) + (32 , \text{in} \times 20 , \text{in}) \]

    • Calculate \(2B\): \[ 2B = 2 \times 64 , \text{in}^2 = 128 , \text{in}^2 \]

    • Calculate \(Ph\): \[ Ph = 32 , \text{in} \times 20 , \text{in} = 640 , \text{in}^2 \]

  5. Add the two results to find the total surface area: \[ \text{Surface Area} = 128 , \text{in}^2 + 640 , \text{in}^2 = 768 , \text{in}^2 \]

Therefore, the surface area of the prism is \(768 , \text{in}^2\).