Final answer:
Columbus calculated his route using his own estimate of the distance to India. He mistakenly used an erroneous estimate by Ptolemy, resulting in him greatly underestimating the Earth's circumference. His miscalculations led him to discover the Caribbean Islands and the coast of Central America, which became known as the 'New World.'
Step-by-step explanation:
Columbus calculated his route using his own estimate of the distance to India. He mistakenly used an erroneous estimate by Ptolemy, which resulted in him greatly underestimating the Earth's circumference. Despite this, his final estimate of the distance to India was close to Strabo's. Columbus believed that he could reach the Far East by sailing west because he knew the Earth was round and believed that by sailing west, he could reach India without the need to go around Africa. However, his miscalculations led him to discover the Caribbean Islands and the coast of Central America, which became known as the 'New World.'