Given that
Cylinder density = 3.75 g/ cm^3
Mass of cylinder = 12.1 g
Diameter = 8.22 cm
Radius, r = diameter /2 = 8.22 /2 cm = 4.11 cm
Now calculate the volume as follows:
Volume = mass / density
= 12.1 g/ 3.75 g/ cm^3
= 3.23 cm^3
Now with the use of volume of cylinder calculate the height as follows:
Volume of cylinder = πr^2h
3.23 cm^3 = 3.14 * (4.11 cm)^2 *h
h = 3.23 cm^3 / 3.14 * (4.11 cm)^2
=0.061 cm