To answer this question you will need to find the total volume the rain barrel can hold. Then find the volume of water that it is currently holding.
Subtract these two amounts to find the total amount of water or can still hold.
Then convert this amount to gallons.
1. V = pi x r^2 x h
3.14 x 1.25^2 x 3.5
V = 17.17 cubic feet
2. Same formula
3.14 x 1.25^2 x 1.5
V = 7.36 cubic feet
3. 17.17 - 7.36 = 9.81 cubic feet
4. 9.81 x 7.5 = 73.575 gallons or approximately 74 gallons.
