Finding the surface area of an object is easy, if you know the formula for how to do it. The formula is (length * height) + (length * width) + (width * height). If we substitute those values in with the values we know here, we will be able to solve this problem. Our expression becomes:
2 [(8 feet * 1 foot) + (8 feet * 3 feet) + (3 feet * 1 feet)]=
=2 [8 feet² + 24 feet²+ 3 feet²]=
=2 [35 feet²]=
=70 feet², meaning that the surface area of this prism is 70 feet².