Answer:

Explanation:
we know that
If the tank half-filled with water is at 20 feet, then the height of the tank is 40 feet
The volume of the cylindrical tank is equal to

we have


assume

substitute and solve for r

![r^(2)=6,000/[(3.14)(40)]](https://img.qammunity.org/2020/formulas/mathematics/middle-school/8xx6x5s5emlbse9f6iowknha0qwpwo7ke1.png)

Find the diameter
Remember that the diameter is two times the radius
