Hello!
To find surface area, all you need to do is add up the areas of all the faces of the prism. Let’s start by remembering some basic area formulas:
Area of a triangle= 1/2*base*height
Area of a rectangle= length*width
First, find the area of each of the little triangles on the sides of the net. The base is 3 ft, and the height is 4 ft. So:
1/2*3*4= 6 ft
There are two triangles of the same size, so multiply that number by 2.
6*2=12
Now, find the area of the top rectangle:
3*8= 24
And the area of the bottom rectangle:
5*8= 40
Finally, add all of those numbers together:
12+24+40= 76 ft^2
That should be your answer!