I need help solving the volume of these triangular prisms.

Volume of a triangular prism:
[tex]\frac{1}{2}b\times h\times H[/tex]Where:
b = 10m
H = 4m
h = ?
To find h, we use the formula:
[tex]h\text{ = }\frac{2}{a}\sqrt[]{S(S\text{ - a)(S - b)(S - c)}}[/tex]Where:
a, b, and c = the lengths of the sides of the triangle.
S is the semiperimeter, which is equal to S = (a + b + c)/2
So:
[tex]\begin{gathered} h\text{ =}\frac{2}{10}\sqrt[]{12(12-10)(12-6)(12-8)} \\ h\text{ = }4.8\text{ m} \end{gathered}[/tex]Now with h, we can use the firs formula to find volume, as follows:
[tex]V\text{ = }\frac{1}{2}\times10\times4.8\times4\text{ = 96}[/tex]V = 96 m³