已知变量x，y满足（x﹣2y）²=（x+2y）²+10，问：x，y是否成反比例关系？如果不是，请说明理由；如果是，请求出比例系数．

阅读理解(A)
    My friend，Victor，is a zoo keeper in the National Zoo．His work is very interesting but it is hard．Sometimes it is dangerous，too．Every morning，the zoo keepers have to get up at five to prepare the food for the animals．Each kind of animal eats special food．For example，the lions must be given meat； the deer must be given grass and leaves； and the parrots must be given fruit and nuts．Sometimes some animals won't let the others eat their food．If this happens，each of them must be fed separately（分离的）．
    Every morning each cage （笼子） must be washed by the zoo keepers．This can be dangerous，especially with lions and tigers．To make the work easier，the animals are locked in the sleeping compartments（ 隔间） while the cages are being washed．When the animals are sick，the zoo keepers must look after them．Each sick animal is kept in a separate cage and given medicine．Sometimes they must be given injection．It is not easy to inject a sick lion!
    All the keepers live near the zoo．Each of them has a small house．There he lives with his family．They do not have holidays on Sundays and special holidays．Instead，each of them has a day off during the week．Each keeperhas a holiday on a different day from that of the other keepers．
    The most important job of the keepers is to look after the safety of the visitors．People must be stopped from doing dangerous things．Many people have been hurt because they did careless things，like putting their hands into the lion's cage．

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下列做法，能达到预期目的的是（        ）                                

（本题满分6分）小明家的房前有一块矩形的空地，空地上有三棵树A、B、C，小明
想建一个圆形花坛，使三棵树都在花坛的边上．
（1）（本小题满分4分）请你帮小明把花坛的位置画出来（尺规作图，不写作法，保
留作图痕迹）．
（2）（本小题满分2分））若△ABC中AB=8米，AC=6米，∠BAC=，试求小明家圆形花坛的面积．