One of Aristarchus theories was the apparent diameter. The apparent diameter was tied in with all of the other theories he had developed. Aristarchus said that the moon's diameter was 2 degrees of the circumference of the moon's orbit. Using an apparent diameter of 2 degrees means that 180 times the radius of the moon (4212.5) would equal the circumference of the moon's orbit.

According to Archimedes (who saved Aristarchus' work, though they never met) Aristarchus actually believed that it was .5 degrees, but said 2 degrees to satisfy his peers. Aristarchus was correct in his real belief that it was .5 degrees.

By combining Aristarchus' methods with Erotosthenes' methods (who discovered the radius of the earth) the radius of the moon would have been 1478.1 miles, which is not that far from the real radius which is 1080 miles.

By Brock, Joe, and Sarah