1. You need a compass that has 6 inches and 15 centimeters on the round semicircle near the top of the compass. You also need a pencil to stick in the side that has a place for a pencil. Make sure that the pencil and the point are equal before you start step 3.
2. Open your compass to the desired length in either inches or centimeters. The number on the compass is the radius of the circle. Multiply the number on the compass by two and you will get the diameter of the circle.
3. Put your point where you want to have the center of the circle. Put your pencil point down and turn the compass around in a circle. Make sure the point doesnt move around or else the circle wont be accurate. The diameter should be twice of the number of inches or centimeters that you started out with.