Both the Galapagos Islands and the island of Naura are on the Equator, but the Galapagos Islands are at 90.30◦W whereas the island of Nauru is at 166.56◦E. How far is it from the Galapagos Islands to Nauru traveling over the Pacific ocean along the Equator, correct to the nearest km ?

  11,481 km

Step-by-step explanation:

Longitude 90.30° W is equivalent to 360° -90.30° = 269.70° E. Then the difference in longitude of the islands is ...

  269.70° -166.56° = 103.14°

The circumference of the earth at the equator is 40,075 kilometers. Hence the distance will be 103.14/360 times that distance:

  (103.14/360)(40,075 km) = 11,481 km

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Additional comment

As always with global distance measures, the result of a calculation depends on the assumptions you make. Attached is another take on the question. Apparently, the distance depends on precisely where in the islands you're measuring from/to. The distance computed above differs from the one below by 136 km. The extent of the Galapagos Islands is on the order of 265 km. So, the number we have computed is at least approximately correct.