the formula to get the volume of the triangular prism is;
V = B x H1 x H2
where;
B = is the area of the base of the triangle
H1 and H2= are the height of the triangle and the height of the triangular prism.
now, to find the area of the base simply use the formula
A = 1/2 B x H
where B is the value of the base and H is the value of the height of the triangle.
given the formula we can derive another formula to get the volume of the triangular prism.
V = 1/2 B x H1 x H2
given the formula, you can now substitute the values
.
V = 1/2 (3 in. x 8 in. x 9 in.)
V = 1/2 (216 in.^3)
V = (216 in.^3)/2
V = 108 in.^3 this is the final answer