ANSWER
320π ft³
Step-by-step explanation
The volume of a cylinder with a radius r and a height h is,
![V=B\cdot h](https://img.qammunity.org/2023/formulas/mathematics/college/yfzbaicbitliay86gi4ymrsrcoxzw1080e.png)
Where B is the area of the base, which is a circle, so the volume is,
![V=\pi\cdot r^2\cdot h](https://img.qammunity.org/2023/formulas/mathematics/college/n3115jxdztqydpk839rmiw7mlgufr9g5b6.png)
In this case, r = 4 feet and h = 20 feet,
![V=\pi\cdot4^2ft^2\cdot20ft=\pi\cdot16\cdot20\text{ }ft^3=320\pi\text{ }ft^3](https://img.qammunity.org/2023/formulas/mathematics/high-school/wfyn9nkro6xbybhlh0t2dollihi3183s9e.png)
Hence, the volume of this cylinder is 320π cubic feet.