Answer:
A)
![(1)/(2)x^3](https://img.qammunity.org/2021/formulas/mathematics/high-school/eh1l1zs6rugqory4twiq75mgg91cs0hyuz.png)
Explanation:
The volume of a triangular prism can be found using the formula
(1)
where
A is the area of the base
h is the height of the prism
Here, the base is a right triangle; the area of a triangle is
![A=(1)/(2)bh'](https://img.qammunity.org/2021/formulas/mathematics/high-school/zp9mthv073eikki4sausz3wgn3bthzva4k.png)
where
b is the base
h' is the height of the triangle
Here, the triangle has the two sides equal, and it is a right triangle, so we have
![b=h=x](https://img.qammunity.org/2021/formulas/mathematics/high-school/cs2rj9o3c7z54exvt70jiu6do2esh2grmw.png)
So the area of the base is
![A=(1)/(2)x\cdot x = (1)/(2)x^2](https://img.qammunity.org/2021/formulas/mathematics/high-school/rs52mrgtuz6f5ssdgsm0aea40iakg5lu1i.png)
We also know that the height of the prism is equal to the leg length of the base, so
![h=x](https://img.qammunity.org/2021/formulas/mathematics/college/zciu3ujqw3l6mea0k948n9mubkbqm8cyti.png)
Therefore substituting into (1) we find:
![V=(1)/(2)x^2 \cdot x = (1)/(2)x^3](https://img.qammunity.org/2021/formulas/mathematics/high-school/kxpym8sjcdbnym0hgpmm8xwd165txs7zcr.png)