Assuming the diameter is 2ft and the height is 4ft the volume is pi*12*4 ft3 or pi*4*123 in3
Since the US is about the only place left using gallons regularly, we'll take the US gallon, which is defined as 231 in3, so the volume is
$${\mathtt{volume}} = {\frac{{\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{4}}{\mathtt{\,\times\,}}{{\mathtt{12}}}^{{\mathtt{3}}}}{{\mathtt{231}}}} \Rightarrow {\mathtt{volume}} = {\mathtt{94.002\: \!980\: \!180\: \!141\: \!345\: \!7}}$$
or volume ≈ 94 gallons
.
Assuming the diameter is 2ft and the height is 4ft the volume is pi*12*4 ft3 or pi*4*123 in3
Since the US is about the only place left using gallons regularly, we'll take the US gallon, which is defined as 231 in3, so the volume is
$${\mathtt{volume}} = {\frac{{\mathtt{\pi}}{\mathtt{\,\times\,}}{\mathtt{4}}{\mathtt{\,\times\,}}{{\mathtt{12}}}^{{\mathtt{3}}}}{{\mathtt{231}}}} \Rightarrow {\mathtt{volume}} = {\mathtt{94.002\: \!980\: \!180\: \!141\: \!345\: \!7}}$$
or volume ≈ 94 gallons
.