Hi Michele. You will first want to convert your inches to centimeters, which will make it easy to figure out litres, because 1 litre is 1000 cm^{3}.
Since 1 inch is 2.54 cm, you can calculate the diameter of the pot and from that, the radius, and from that, the area of the bottom of the pot (using A = PI*r^{2}).
The volume is the area times the height, so that means the height is the volume divided by the area. Use this relationship to get the height in centimeters. If you need to convert to inches, use the conversion ratio 2.54 cm : 1 inch again.
Stephen La Rocque>
