13. how much closer were the continents when columbus crossed the atlantic in 1492?

1,317.5 cm / 13.175 m

Explanation:

The Atlantic Ocean is an ocean that is increasing in size. This is due to the divergent plate boundary located in its central part, running from north to south of it. The divergent plate boundary is between the North American and Eurasian tectonic plates.

The eastern part of the North American plate and the western part of the Eurasian plate are moving away from each other. The mid-ocean ridge that exist at the divergent boundary is constantly active and creating new crust on the ocean floor, pushing the old crust away, thus moving the two plates in opposite direction.

The annual rate of moving away from each other between the two plates is about 2.5 cm. Considering that Columbus crossed the Atlantic Ocean 527 years ago, it turns out that the two continents were 1,317.5 cm closer to each other, or that would be 13.175 m closer.

That is not really a big difference, but over time, with this process continuing, the continents will move away significantly, creating a much large ocean between them.