What is the circumference of the earth's moon?

since the earth is not a perfect cube

http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html

Once the atmosphere cools at night, the visual field occupied by the image of the moon should remain mostly constant, which will allow the calculations to be computed. We know the velocity of the moon, since we know the distance from earth to it, and since it orbits the earth once every 24 hours (this velocity is relative to the earth's center).

D = mean distance from earth to moon
v = mean velocity of moon (assuming roughly circular)
t = time taken for 1 orbit (86400 s)


2 * pi * D = O
O / t = v

Now, measure the arc and the time it takes to complete said arc, then you should be able to take the ratio of the two velocities. To be very accurate, depending on the time of year, you may need to use calculus to compensate for the secant error types.