Eratosthenes determined the circumference of earth by conducting an experiment. put his steps in order as they correlate to the scientific method. 1. state the problem: 2. make a hypothesis: 3. make observations: a) if the sun casts shadows at different angles at the same time of day in different places, we can determine how much earth curves. b) in syene, the sun's rays are vertical at noon. at the same time in alexandria, the rays are 7.2 degrees from the vertical. c) how can we prove earth is round and calculate its circumference?