A rectangular prism has a length of 7 cm, a width of 3 cm, and a height of 2 cm. What is its total surface area?

1 answer

To find the total surface area of a rectangular prism, we can use the formula:

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

Where:

  • \( l \) is the length,
  • \( w \) is the width,
  • \( h \) is the height.

Given:

  • Length (\( l \)) = 7 cm
  • Width (\( w \)) = 3 cm
  • Height (\( h \)) = 2 cm

Now, let's calculate each area:

  1. Calculate \( lw \): \[ lw = 7 , \text{cm} \times 3 , \text{cm} = 21 , \text{cm}^2 \]

  2. Calculate \( lh \): \[ lh = 7 , \text{cm} \times 2 , \text{cm} = 14 , \text{cm}^2 \]

  3. Calculate \( wh \): \[ wh = 3 , \text{cm} \times 2 , \text{cm} = 6 , \text{cm}^2 \]

Now, substitute these values into the surface area formula:

\[ \text{Surface Area} = 2(21 , \text{cm}^2 + 14 , \text{cm}^2 + 6 , \text{cm}^2) \]

Calculating the sum inside the parentheses:

\[ 21 , \text{cm}^2 + 14 , \text{cm}^2 + 6 , \text{cm}^2 = 41 , \text{cm}^2 \]

Now, multiply by 2:

\[ \text{Surface Area} = 2 \times 41 , \text{cm}^2 = 82 , \text{cm}^2 \]

Thus, the total surface area of the rectangular prism is:

\[ \boxed{82 , \text{cm}^2} \]