Last spring equinox, brothers Doug and Ryan Euclid were standing at the equator looking out to sea. Doug was standing on the shore, while Ryan was standing above him on top of a cliff. Their eyes were 2m and 23m above sea level, respectively. When Doug saw the sun set, he called out; 26 seconds later Ryan observed the sun setting.

Doug and Ryan were observant and knew the time it takes the Earth to rotate once. The brothers estimated the diameter of the Earth.

What was their estimate to the nearest 100km?