Question

The figure below is a net for a right rectangular prism. Its surface area is 432 m2 andthe area of some of the faces are filled in below. Find the area of the missing faces,and the missing dimension.

Answer 1

The surface area is the sum of all the areas in the given prims, then we have:

`SA=72+72+48+48+2A`

Plugging the value for the surface area and silving for A we have:

`\begin{gathered} 432=72+72+48+48+2A \\ 432=240+2A \\ 2A=432-240 \\ 2A=192 \\ A=(192)/(2) \\ A=96 \end{gathered}`

Now that we know the missing area we can know the missing dimension:

`\begin{gathered} 96=8x \\ x=(96)/(8) \\ x=12 \end{gathered}`

Therefore the missing length is 12.