Answer some of my math questions i only have one attempt left to get it right

Maybe you didn't see but it's 9 ft, not yard.

1 ft = 0,333 yd

9 ft = 3 yd

Ok we'll start by calculate the triangle

Because of the 90°, you will use 3yd for the height and 4yd for the base

(3•4)/2 = 6 square yards

For the third dimension,
6•7=42 cubic yards

Total volume = 42 cubic yards

Y=-2/3- 3
I believe this is right.