Answer:
628.
Step-by-step explanation:
We need to calculate the radius of the cylinder :
40/2 = 20 feet
We then will calculate the volume of the whole cylinder:
[tex]V = \pi * r^{2} * h = 3.14 * 20^{2} * 120 = 1256[/tex] cubic feet.
However, Wayne greenhouse is just a half of a cylinder, so it's volume are:
[tex]1256 / 2 = 628[/tex] cubic feet.
I'm vietanh and have a good day!