Answer:
97.2 m³
Explanation:
The volume of a triangular prism is half the volume of a rectangular prism with the same length, width, and height.
V = 1/2LWH
V = 1/2(9 m)(7.2 m)(3 m) = 97.2 m³
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Additional comment
The relation we used above comes from the more general formula for the volume of a prism:
V = Bh
where B is the area of the base.
You know a rectangular base will have an area of ...
A = bh
and a triangle with the same base and height will have an area of ...
A = 1/2bh
That is, the base area of a triangle is half that of a rectangle with the same dimensions. When we use this fact in the volume formula, we find the volume of a triangular prism is 1/2 that of a rectangular prism with the same length, width, and height.