First, you have to find the area of each garbage can- v$v=\pi rh ^{2}$ and our radius is half of our diameter. Substituting our values, we get (Pi)(.75)((.5)^2) for an answer of 0.58904862254 cubic meters, but don't round till the very end. To find how much they need, we divide the amount we want to dispose- 10 cubic meters by the amount one garbage can will hold- 10/0.5890486224 for an answer of 16.9765272634 we can't have 16.9765272634 trash cans, so we round to 17. We will need a minimum of 17 trashcans.