I was wondering what the surface area was. for this prism?

What you are using is a "net." The net of a solid figure is formed when a solid figure is unfolded along its edges and its faces are laid out in a pattern in two dimensions. Nets of rectangular prisms are made up of rectangles and squares

Finding the areas of each of the rectangles and squares of the net of a rectangular prism and adding up those areas gives the surface area or total surface area of the prism.

For this problem, it would be the area of one triangle times two (since there are two) and the area of a rectangle times 3 (since there are three rectangles). Let's start with the triangles...

Triangles

The formula for area of a triangle is 1/2bh. The base is 8 and the height is 4, so 8*4 = 32/2 = 16. Now 16 *2 = 32, meaning that the combined areas of the triangles is now 32.

Let's try rectangles...

Rectangles

The formula for area of a rectangle is simply bh. Base is 8, height is 15, meaning the product is 120. Multiply by 3 and you get 360. The combined areas of the rectangles is now 360.

Now add the two values for the surface area:

360 + 32 = S.A. = 392 units^3

I hope this helps. If you have any more questions, please feel free to post them and someone will be able to help you, whether it's myself or others. Please leave a like, rating, and if possible, Brainliest. Have a great day!