Question

The volume (V) of a cylinder can be determined by using the formula
V
=
π
r
2
h
,
where
r
=
the radius of the base, and
h
=
the height of the cylinder.



Students are creating tubes to mail rolled-up posters of a class photo, and they need to determine the radius of the mailing tube.



Which equation below will solve for r?


r
=
√
V
π
h


r
=
√
V
−
π
h


r
=
V
2
π
h


r
=
V
−
π
h
2

Answer 1

Start with V = π r^2 h. Divide both sides by πh:

r^2 = V / (π h).

Take the square root (r ≥ 0):

r = sqrt( V / (π h) ).

So the first option is correct.