Who studied Ptolemy's work and found that if Asia were as far east as Columbus had thought, it would cover the Earth? Vespucci, Balboa, or Magellan?

The correct answer is the first option, Vespucci. Amerigo Vespucci was an Italian explorer who studied the work of Ptolemy and, in doing so, found that if Asia was as far east as Columbus had thought it was, it would cover half the Earth. He not only discovered that Asia was in fact smaller than what Columbus had thought it was, but also that the size of the Earth was much bigger than what most people thought it to be.