Part A:
Let:
V = Volume
r = Radius
h = Height = 20 ft
The volume of a cylinder is given by:
[tex]\begin{gathered} V(r)=\pi r^2h \\ so\colon \\ V(r)=20\pi r^2 \end{gathered}[/tex]
Answer for part A:
[tex]V=20\pi r^2[/tex]
Part B:
From the previous equation, solve for r:
Divide both sides by 20π:
[tex]r^2=\frac{V}{20\pi}[/tex]
Take the square root of both sides:
[tex]\sqrt[]{r^2}=\sqrt[]{\frac{V}{20\pi}}[/tex]
Answer for part B:
[tex]r=\sqrt[]{\frac{V}{20\pi}}[/tex]
Part C:
Using the previous equation:
[tex]r=\sqrt[]{\frac{V}{20\pi(3.14)}}[/tex]
Graphing the function:
