Answer:
A
Step-by-step explanation:
volume of a cylinder:
[tex]V=\pi r^2h[/tex]
where r = radius and h = height
We are given the volume (V) and the height (h) and we need to find the radius (r).
To find the radius we are going to want to plug in the given values into the formula for volume of a cylinder and solve for r
so, * plug in given values *
[tex]400= \pi r^28[/tex]
Now we solve for r
step 1 take the square root of each side
[tex]\sqrt{400} =20\\\sqrt{\pi r^28} =\sqrt{\pi } 4*r\\[/tex]
now we have [tex]20=\sqrt{\pi } 4*r[/tex]
step 2 divide each side by sqrt (π) 4
[tex]\frac{20}{\sqrt{\pi } 4} =3.989 \\\\\frac{\sqrt{\pi } 4*r}{\sqrt{\pi } 4}=r\\[/tex]
we're left with r = 3.989
Finally we round to the nearest whole number and get that the answer is A.4
