Question

Find the surface area of the prism choose the correct units

Answer 1

We have a rectangular prism, with dimensions 7 ft tall, 1 ft wide and 4 ft deep.

The surface area of the prism is the sum of the area of all their faces.

We can start by listing the faces. We will have 3 pair of faces:

- One pair of 7 ft * 1 ft

- One pair of 1 ft * 4 ft

- One pair of 4 ft * 7 ft

Then, we can write and solve the expression for the surface area as:

`\begin{gathered} A=2\cdot A_1+2\cdot A_2+2\cdot A_3 \\ A=2\cdot(7\cdot1)+2\cdot(1\cdot4)+2\cdot(4\cdot7) \\ A=2\cdot7+2\cdot4+2\cdot28 \\ A=14+8+56 \\ A=78\text{ ft}^2 \end{gathered}`

Answer: the surface area is 78 square feet.