Hello!
As you can see, two of the triangles that we see that are made from the lengths we are given make up one face of the pyramid. We can use the triangle formula without multiplying by 1/2 to find the length of one face.
30(45)=1350
Now we multiply this by four to find all of the sides.
1350(4)=5400
We find the area of the square base
30(30)=900
Finally, we add up our lengths.
5400+900=6300
Therefore, our answer is C) 6400 yards²
I hope this helps!