Answer:
342yd^2
Explanation:
The way I find surface area is by laying out the box and finding the area of each square seperately and then adding them together.
First, I placed the 7 on the wing to the side because that is the width.
Next, I placed the 13 on the long side of the big box because that is the length.
Then, I placed the 4 on the small side of the big box because that is the width.
After that I just did the multiplication for each box.
2(7•13) + 2(7•4) + 2(13•4) = 342
You can apply this same strategy to any surface area problem like this. The format will change based on the shape but that's pretty much it. Hope this helped