我们都知道地球是个椭圆形球体,因而很自然地会发问:在我们脚下的地球那一边是什么地方呢? 地球两头相对的两点,地理学上叫做“对跖点”,要知道我们脚下是什么地方,可以用求对跖点的公式求出。求对跖点的公式是:假若甲地的纬度是x°,经度是y°;它的对跖点乙地的纬度也是x°,经度是180°-y°。甲地若是北纬,乙地就是南纬;甲地若在东经,乙地就在西经,两地遥遥相对。为了便于记忆,我们可以编成两句歌诀:“纬度相同分南北,经度互补各东西”。“互补”就是几何学上的补角关系,即两地的经度加起来等于180°。现在我们就来找找我国一些 We all know that the Earth is an oval sphere, so it is natural to ask: Where is the side of the earth under our feet? The two opposite ends of the earth, geographically called “right metatarsal”, know that our feet are Where can we find the formula on the plantar point. Find the plantar point formula is: If the latitude of a is x °, longitude is y °; its latitude to the plantar point B is x °, longitude is 180 ° -y °. If A is north latitude, B will be southern latitude; if A is east longitude, B will be west longitude, and the two places will be far away from each other. In order to facilitate the memory, we can make up two verses: “the same latitude north and south, longitude complement each other.” “Complementarity” is the geometrical complementarity, that is, the longitudes of the two places add up to 180 °. Now we come to find some of our country