The volume of a prism is Area of the base multiplied by the height.
From the problem, the base area is 2 1/2 cm^2 = 2.5 cm^2 and the height is 4 1/2 cm = 4.5 cm.
The volume will be :
[tex]\begin{gathered} V=2.5\operatorname{cm}\times4.5\operatorname{cm} \\ V=11.25\operatorname{cm}^3 \end{gathered}[/tex]The answer is 11.25 cm^3 or 11 and 1/4 cm^3