题目

The park bench was deserted as I sat down to read beneath the branches of an old tree， with good reason to frown， for the world was intended to drag me down． At this time， a boy approached me． He stood right before me， and said with great excitement， Look what I found!In his hand was a flower， and what a pitiful sight， with its petals （花瓣） all worn． Wanting him to take his flower and go off to play， I faked a small smile and then turned to the other side．But instead of leaving， he sat next to my side and placed the flower to his nose and declared， It really 暑假期间，小亮到邢台寒山风景区--景区主峰寒山垴（为邢台市太行山段最高峰，位于内邱县境内）旅游，导游提醒大家上山要多带一件衣服，并介绍山区气温会随着海拔高度的增加而下降，沿途小亮利用随身带的登山表（具有测定当前的位置的海拔高度和气温等功能）测得以下的数据：海拔高度x（米）300400500600700…气温y（℃）29.228.628.027.426.8…（1）如图以海拔高度为x轴，根据上表提供的数据在下列直角坐标系中描点并连线．（2）观察（1）中所画出的图象，猜想y与x之间函数关系，求出所猜想的函数关系表达式．（3）如果小亮到达山顶时，只告诉你山顶气温为20.2℃，你能计算寒山垴海拔高度大约是多少米？