Currently, this value is obtained from the reference ellipsoid method pioneered by John Hayward, but its first measurement was conducted using the height of a (*) shadow cast in a well in Alexandria and Syene by Eratosthenes.
A precise value for this quantity was obtained by Jean Fernel and confirmed by Richard Norwood using the recently invented surveying chain. A value for this quantity is derived in the first section of the Aryabhatia of Aryabhatta, whose work was promoted by the middle of the 10th century C.E. by al-Biruni, who also measured this value. Jean Picard used Snell's triangulation method to measure this quantity. Currently, this value is obtained from the reference ellipsoid method pioneered by John Hayward, but its first measurement was conducted using the height of a (*) shadow cast in a well in Alexandria and Syene by Eratosthenes. For 10 points, identify this value which is approximately 40,000 kilometers, the size of the great circle of our planet.
A precise value for this quantity was obtained by Jean Fernel and confirmed by Richard Norwood using the recently invented surveying chain.
circumference of the earth [accept answers like "radius of the earth" or "diameter of the earth" but prompt on "size of the earth"]