Answer:
[tex]240 in^3[/tex]
Step-by-step explanation:
I'm assuming the pyramid base has to fit the prism, else the answer would be "as big as you want.
Now if you compare the formulas for the volume of a pyramid and a prism, you notice that the only difference is a factor of 1/3 (it will take 3 pyramids to fill a prism).
Volume of the prism is the product of the sides, ie [tex]15\cdot8\cdot6 = 720 in^3[/tex]. Volume of the pyramid will be 1/3rd of that, or [tex]240 in^3[/tex]
