<P> The surface area of the circular disk is π r 2 (\ displaystyle \ pi r ^ (2)). </P> <P> The radius of the circular disks, defined such that the x-axis cuts perpendicularly through them, is </P> <Dl> <Dd> y = r 2 − x 2 (\ displaystyle y = (\ sqrt (r ^ (2) - x ^ (2)))) </Dd> </Dl> <Dd> y = r 2 − x 2 (\ displaystyle y = (\ sqrt (r ^ (2) - x ^ (2)))) </Dd>

Which unit is not a measurement of volume