How many straws would you need to build a pentagonal prism?

To build a pentagonal prism, you would need a total of 30 straws. This is because a pentagonal prism has two pentagonal bases and five rectangular faces. Each pentagon requires 5 straws, totaling 10 for both bases, while the 5 rectangular faces connecting the bases contribute an additional 15 straws, leading to 10 + 15 = 25 straws in total.