Answer:

Explanation:
So, let's start by calculating the surface area of the base, which in this case is a square. The area of a square can be calculating by taking any of the lengths and squaring it, since all the sides should be equal if it's a square. Since one of the sides of the square is 3 yd, you have the equation:
. Now to calculate the area of the four triangles. The area of a triangle can be calculating by using the formula:
, and in this case the base is 3 yd, and the height is 5 yd (lengths can be determined by looking at the given values in the diagram). But there's 4 of the triangles so we multiply it all by 4, and this gives you the equation:
. So now all that's left is to add this to the area of the square which gives you the equation:
which is the surface area