Thus, the distance of 800 km between the two cities would automatically become a circumference of one-fifth of the total circumference. So to complete the whole circle, we now need 50 circles of 800 kilometers. To be clear. Since a circle has 360 degrees, 360 degrees is 50 times 7.2 degrees. So to get a 360-degree circle, you now need to combine 50 of the 7.2-degree circles. Each of these 7.2-degree circles has a circumference of 800 km, so if we add 50 of these circles, we now have a full circle. So 50 times 80 kilometers is equal to 40,000 kilometers, so his total circumference is 40,000 kilometers (it would be easier to understand if you look at the first picture below).