The volume of a cylinder is 980 in cubed.
the height of the cylinder is 20 in. what is the radius of the cylinder?
express your answer to the nearest hundredth.

A cylinder is basically lots of circles stacked on top of each other so equation for volume of cylinder is (area of circle formula) times height

area of circle formula=pi times r^2
so volume of cylinder=pi times r^2 times height

volume=980 in
volume=pi times r^2 times height
height =20
subsitute
980=pi times r^2 times 20
divide both sides by 20
49=pi times r^2
divide both sides by pi
=r^2
square root both sides (remember that ) so

==r

try to make there be no radical (√) in the bottom so multiply top and bottom by

times ==radius≈(if aprox pi to 3.14)3.94933 in

the answer is (7√pi)/pi in or aprox 3.95 in