Volume of a cylinder

A battery in the shape of a perfect cylinder has a volume of 15 cm³. Its height is 6 cm. Find the radius of the battery.

h= 6 cm

volume= 15 cm³

We know the formula for the volume of a cylinder is:

$h\pi { r }^{ 2 }$

So, $15=6\pi { r }^{ 2 }$, then we divide both sides by 6. $\frac { 15 }{ 6\pi } =\frac { 6\pi }{ 6\pi } { r }^{ 2 }$
This simplifies to: $.7958={ r }^{ 2 }$. Taking the square root of both sides gives us: $.89={ r }$. In other words, the radius of the battery is a little less than one centimeter.