题目

The Atlantic Ocean is one of the oceans that separate the Old World from the New. For centuries it kept the America from being discovered by the people of Europe. Many wrong ideas about the Atlantic made early sailors unwilling to sail far out into it. One idea was that it reached out to “the edge of the world” . Sailors were afraid that they might sail off the earth. Another idea was that at the equator(赤道) the ocean would be boiling hot. The Atlantic Ocean is only half as big as the Pacific, but it is still very large. It is more than 4,000 miles (6,000 km) wide where Columbus crosse 一把展开的扇子的圆心角是120°，扇子的骨架长是30厘米．这把扇子展开所占的面积＝________．