The mean radius of earth is : 6,731.0 kilometers
The mean radius of Earth moon is : 1,737.5 kilometers
The difference in their circumference is given as :
Circumference = 2 * Pi * r where Pi = 3.14 , r = radius
Applying the formula for Earth will give.
C= 2 * 3.14 * 6731 = 42,292.12
For the case of the moon
C= 2 *3.14 * 1,737.5 = 10,917.03
The difference in there circumference is ;
42,292.12 -10,917.03 = 31375.08
Answer
31375.1 kilometers