Answer:
Option C. ![42\ yd^{3}](https://tex.z-dn.net/?f=42%5C%20yd%5E%7B3%7D)
Step-by-step explanation:
we know that
The volume of the triangular prism is equal to
![V=BH](https://tex.z-dn.net/?f=V%3DBH)
where
B is the area of the triangular base
H is the height of the prism
Convert 9 ft to yd
Remember that
1 ft=1/3 yd
9 ft=9*(1/3)=3 yd
<em>Find the area of the base B</em>
![B=\frac{1}{2}(3)(4)=6\ yd^{2}](https://tex.z-dn.net/?f=B%3D%5Cfrac%7B1%7D%7B2%7D%283%29%284%29%3D6%5C%20yd%5E%7B2%7D)
we have
![H=7\ yd](https://tex.z-dn.net/?f=H%3D7%5C%20yd)
substitute the values in the formula
![V=BH](https://tex.z-dn.net/?f=V%3DBH)
![V=(6)(7)=42\ yd^{3}](https://tex.z-dn.net/?f=V%3D%286%29%287%29%3D42%5C%20yd%5E%7B3%7D)