The tires on the car are circles, so to calculate how far it travels on one revolution, we can figure out the circumference of the tires. The formula for circumference of a circle is pi x diameter. The diameter is 2 centimeters, so here are all of the potential answers depending on what the question is asking:
In terms of pi, it would simply be 2π.
In terms of 3.14, the answer would be 6.28.
In terms of being accurate, it's 6.283185…
There is also another name for 2π; tau. I hope this answered your question!